The owner of Berrow (sorry I haven't a contact) does allow visits sometimes - not sure of the current state of play there. Be careful - there is a ROAD (small one) running across the westerly end - if a car appears you will both get a shock. Also an interesting change of height half way down the runway.
Neither Ledbury (or Dymock International Airport as the sign has it) or Berrow would have Avgas,
AFAIK.
Gloucester does though, as pointed out above.
I agree with mossie1960, Ledbury. Plenty of length, about 600m I think.