1, this hobby is not supported in the way other similar are, ie Airshows.
2, it can be a massive expense to find that what you are looking for is not there.
3, EBAY !
4, A lot of deals go on here even though they are not supposed too.
5, secrecy, collectors like to keep things close to home especially where to get bargains.
As Andy says, 2 per year one north one south or even mid country. I would love to attend these events but it really would only be a jolly outing and the best part of £120.00 quid for the day. seeing a museum would be a bonus and maybe linked to an airshow day is my thoughts but again I doubt I would be parting with much cash to the vendors unless it was very special.
This is not a downer its just some facts as I see them.
Good luck to all organisers of these events and I do take my hat off to the effort put into running them.
TA