Big, or big?
My local growing up was Wolverhampton which always seemed to be a pretty decent size in the 80s and was on for 3 days on a bank holiday weekend. One year we went twice as there was an excellent Swiss layout which really captured my imagination, it was modelled down to even the same cars being parked at the station as had been there during the builder's photo survey.
A chap could still smoke a pipe indoors at that time and that sense memory stays with me.
Later I spent a couple of holidays staying with my grandad near London and he took me in to the Central Hall show, I was blown away! I saw Pete Wilson's Chwarel Cwm Bach there (008 rather than 009) so it must have been the very late 80s or early 90s.