What's with the biplanes?

[ragged]

I see them a lot.
Up in the sky, I mean, lol.
Am trying to figure out if this area is popular with some Biplane leisure company (like this one). Or why else biplanes are so common here.

Anybody know?

large amount of airfields?

not really, I don't think so. Nearest one I can think of (Northrepps) is about 8 miles away and is private (club only, mostly model aeroplanes I think) and therefore quite small.