In a week that marks the 375th anniversary of one of the deadliest battles fought on Kentish soil, KentOnline can reveal exclusive evidence that re-writes English Civil War history.

Just as most scholars agree the Battle of Maidstone itself took place in the County Town on June 1 1648 – the door of All Saints Church still has the dents from musket shot to prove it – the accepted view had been that the even more famous Battle of Naseby of 1645, had taken place, as its name suggests, in Naseby, Northamptonshire.

Wrong. That took place in the borough of Maidstone too – at least that’s according to an old video we found of it on YouTube.

In footage that should send shockwaves through academic circles, Parliamentary forces are seen lined up not on Naseby Ridge, but on the slopes of the Greensand Ridge near Boughton Monchelsea Place.

And instead of inflicting a decisive victory over the Royalists, they simply turn and run away. The repercussions will have academics across the country choking on their Weetabix.

Ah, but Weetabix is the key word, and it’s time to stop the charade. Anyone over a certain age will recall this footage has turned up before, not so long ago in historical terms, on our TV screens in the early 1990s.

And yet as recognisable as this old Weetabix advert is to many, few will know it was indeed shot in the deer park at Boughton Monchelsea Place, near Maidstone in 1989.

The iconic advert begins with a shot of upwards of 1000 Roundhead forces amassed on the ridge before the aforementioned ‘Battle of Naseby’, waiting for the arrival of the Cavaliers…

“I dunno what’s happened this morning,” says one of the footsoldiers to a fellow pikeman. “The battle was supposed to start an hour ago.”

“Here comes someone now,” replies his pal, and there’s an expectant rattle of pikes as a lone cavalier rides up to the ranks, and addresses a mounted Parliamentary leader.

“Sorry about the delay,” says the long-haired Cavalier general, in a cavalier fashion. “My lot won’t budge until they’ve had their Weetabix. But we’re ready to start now.”

Listening closely back in the ranks, Footsoldier No.1 adopts a concerned expression as he announces “They’ve had their Weetabix” to his friend, who replies in growing fear: “they’ve had their Weetabix?”.

The news quickly spreads down the line before “they’ve had their Weetabix” turns into a massed call of retreat, and the forces down weapons to run back up the hill... as a voiceover man calmy asks: “Have you had your Weetabix?”

If you watched TV back then you’ll probably remember it – and surely if you were around in Boughton Monchelsea at the time of filming in 1989, you’ll also remember the arrival of more than 1000 armed men surely needed to film such a scene in the days before CGI…

But finding anyone who does remember it in the village proved a difficult task, so KentOnline contacted Weetabix, who dug out some footnotes on the advert which included a list of the creative team, including one producer Charles Crisp.

Now heading up his own advertising department, Charles was a young TV producer in his late 20s at the time of the advert, but was able to reveal why the ‘army’ involved didn’t cause too much of a stir.

“This is the thing, it didn't involve that many people,” said Charles. “There were about 150 people, and I think they came from a local reenactment society. Obviously they love doing that - it was great opportunity and they get to be on film.”

These days computer effects would be used to expand the 150 men into a huge army, but instead the team used a different kind of film trickery to spread the army across the slopes of the Greensand Ridge.

“It was early days,” added Charles. “Everything was shot on film but it was quite clever. We had a static camera and we moved all the army down. We had 150 people and shot them, showing them running away, then moved them down 150 yards to a peg and they ran off again, and so on.

“We combined that in post production to give the impression of an army of about 1000 people. These days it would be nothing, it would all be done on CGI. It was quite clever doing that at that time.”

While Charles admits his memory of shooting the advert isn’t comprehensive, he believed the proximity of a reenactment society was key to the location being chosen.

“I remember them coming along and some of them camping out in period tents and cooking food over their fires,” he added. “They came with all their own gear - the wardrobe and pikes, which made it a little cheaper, but we had to cater for them so there was still a huge amount of catering to be done.”

Chris Scott, one of the Roundhead commanders involved, also recalled issues with the catering, and said they almost prompted his troops to stop acting and turn genuinley militant.

“We joined with a few other regiments and who wore the same coloured coat and went over the day before,” said Chris, a commander with the Colonel Nicholas Devereux Regiment, part of the Roundhead Association and English Civil War Society. “We slept over in some sort of big shack, somewhere way away on a farm, and we had to get up at some unearthly hour for a 6am start.

“We got there at 5ish and they said right, everyone on the field, and we were a bit p***** off because we weren't even offered a cup of coffee.

“We did some filming and it was pre-CGI and the technique was to do lots of different takes down this long field, with a piece of string marking a line, which we all moved down. We filmed it about eight times and rotated the front rank each time.

“It was quite amusing. We just thought it was quite funny that we were running away from an imaginary army.”

But as the morning drew on, Chris’ troops were growing hungry, and less enthusiastic.

“The catering became quite an incident,” he added. “We got to about 10am having been at it since 6am, when they allowed us a breakfast break.

“We all got in a big queue but after the first 20, the caterer said he didn't have enough so he was only going to do bacon rolls. I went down the line and asked if people would be happy with that, and they said 'yes if it's big enough', so he served about 50 bacon rolls and then said he wasn't going to do any more.

“I asked him how he was going to serve lunch, and he said ‘what?’ And I said ‘your van's going to end up on its side’. After that he managed to find some more bacon rolls.”

Weetabix wasn’t on the menu, but Chris added: “One of the blokes in the queue said 'we'll even have Weetabix - or cardboard-bix I think he called it.

“We had done quite a lot of filming, so we knew what it's like. It's 90% boredom and 10% chaos, and it was ok in the end.”

But the trouble didn’t end with breakfast.

“One of the actors went on to do a lot of TV but kept forgetting lines,” said Chris. “There's a longer version in which the two actors have to say something about Weetabix and why they were running. This one bloke kept forgetting lines, falling over and objecting to running through thistles - I don't know if he was getting paid by the hour.

“One of my lot said 'do you mind if I talk to him?' I said ok, and he told him 'if you fall down again or forget your lines there are about 20 people who are going to run over you?' He suddenly started remembering them and didn't fall over.

“The TV people were a great source of amusement to us. A couple of us decided to get some lobster with the actors - they had a special bus for people like the chap who forgot his words. A few people decided to investigate the bus.

“We all got paid and got our travel covered, but it was nothing like working for Disney who gave us huge amounts. We did surround vision for Disneyland Paris, filming a battle between the English and the Highlanders.”

Despite the chaos surrounding catering, producer Charles says he still looks back on the advert with pride.

“It was 1989 and I was 29. I'd been a producer in TV for about five years,” he added. “Paul Weiland was the director - he went on to do Johnny English 2. He was a big name back in the day and went on to have an illustrious career. Between us we did a lot of commercials.

“I think it stood the test of time as an ad. Someone said the creatives who work at Weetabix say it was still brought up as one that was generally remembered.

“I'm very pleased with it, it was really good. I was watching it again yesterday and I thought - the framing is all wrong because it's on YouTube rather than TV - but if you got rid of that you could still run it today. I think they still use that line - “have you had your Weetabix”?

Well, he’s not wrong, and we’ve used it more than enough times in this article, and so we should add that we’re not angling for any free boxes of the stuff.

We ate more than enough of that in the 80s and 90s. If they can send any free Shreddies though that would be fine.