Rally at a show

Have a look at cc centres rally programmes,they will be ones who are more likely to run them in conjuntion with any shows in their areas,

Cheshire centre holds one at the Cheshire show. 

http://www.cheshirecentre.co.uk/rally-243.html

I think there is usually a Rally near The Westmorland Show (2nd Thursday in September).

i don’t know who runs it - maybe CCC, but there are caravans in the field opposite the Crooklands Hotel.

7 -11th June Detling (Kent county showground) South London centre are running a rally to coincide with a Caravan Show there, we went last year 

Alison

Royal Cornwall Show - 7,8,9 June 2018 - has its own caravan and Camping park alongside - it sells out quickly. Details on their website.