Charlestown Fete from the 1960s

This vintage home movie is entitled 'Charlestown Fete' and dates from the 1960s, but which Charlestown was it filmed in?

First a bit of information about the film. It was shot on Ilford standard 8mm film, and although there is no date on the plastic box the film is in, I would estimate that it was likely taken in the 1960s.

I did some google detective work to try to find out where this film could have been taken. When I did a search for Charlestown I came up with multiple alternatives:

• A town in Cornwall.
• A town in County Mayo, Ireland.
• Many towns with that name in the USA.

There is actually little in the film which shows the geography of the town other than the opening sequence with a marching band parading down the street, so the pictures I could find of the towns in Ireland and Cornwall didn't supply a match. The images of the cars which appear later in the film would suggest a UK or Ireland location, so I think it is one of those two.

The subject matter of the film gives me few clues either, so I'm hoping that someone who views this film will have a better knowledge of history and can interpret the film better than I. It seems to show a battle reenactment played out by school age children. The uniforms the children are wearing seem to be napoleonic era British army uniforms, but I'm not by any means an expert in history so I can't be sure.

I did find this wikipedia article about the Battle of Charlestown in the US, but the cars in the film suggest a UK location so I don't think it is that.

If anyone can supply an explanation or good guess as to the location and events in this film, please use the comments form below to let me know.