https://www.theguitarshow.co.uk/
I went to this last year, same venue. A good show, with enough bass gear to make for an enjoyable Sunday afternoon. Parking right at the venue is tight, but you can spill out into the streets of the surrounding industrial estate.
Well organised and not too loud (amps on only for 10 minutes each half hour and everyone at sensible volume, and a separate acoustic hall)