I've been flying with Booker Aviation (formerly Airways Flying Club) for about a year, building hours in a PA-28. I have flown with several of the Booker Aviation instructors to get signed-off to rent solo (I did my PPL in the USA) and also to improve my skills e.g. crosswind landing practice. The instructors are friendly and professional, and there's quite a range of personalities
so you can find one you get along well with. The office staff are also helpful, the aircraft are well-maintained and the PA-28 has reasonable availability if you plan a little ahead.
Some things to be aware of: the noise abatement procedures are quite complex and are applied very strictly. The airspace nearby is also complex (CTA / TMA for Heathrow and Luton, Brize, ...). You might spend some additional time getting familiar with the airport - but it's all relative and I have heard that Stapleford and Bournmouth are fairly complicated too. There isn't an ILS at Wycombe which for you might want to keep in mind if you are planning to do the IR at the same place are your MEP / CPL.
Overall, my experience has been positive. If you want any more information, feel free to PM me.