I would recommend Inverness they fly most days of the year. There is a nearby pub/hotel which does good cheap food about a mile away. Instructors are all good, CFI is an examiner. Reasonably cheap well its the cheapest I know of. As for aircraft availability its possible to turn up early on a Sat or a Sun and get an aircraft the same day. Cant do that in the south with places with much larger fleets. There is the added bonus of great scenery - even the circuit isnt boring and the QXC landing fees are arround £4 at each airfield. As you already have a PPL you should find it easier.
oh Oil I had fewer days cancelled due to weather in Inverness than I did on the South Coast