This is only a 'maybe' but Spade Oak Pit might be a good choice. It does hold some very good fish of other species and this may well include perch but I cannot be specific about it......
I strongly suggest you do a bit of foot work and walk the place a few times, say over weekends when more anglers are about, and ask a few questions. It is a fairly big water but is does have a few features such as islands and in some parts it is quite deep (and in others shallow) so no real reason why good perch cannot be caught.
As Ray Roberts has said, you cannot expect anglers to give out info that has taken years to collect, so if you are serious it's really up to you to make some effort. You could do a lot worse than take a rod and plummet and check some depths at various places around the pit to start to build a picture of the bottom. This, along with talking to anglers, will give you a head start and probably save you time in the long run................
I'm not sure of the perch potential of the pits along the Marlow by-pass, but again YOU HAVE TO PUT IN THE TIME and research the place. Both are big and hold excellent tench but they are rarely fished IMHO.
Whatever you decide, don't expect instant success as all the above waters are what I would class as 'difficult' BUT the big fish are there..........
Good luck
ps The Thames, from the bridge over the Marlow by-pass going downstream toward the 'castle' on the opposite bank, has produced some good perch over the years, but again you need to spend time checking it out.
Anyway that's enough info to keep you going for 3/4 years or so !!!