HAve you tried Brawlings Farm, Brawlings LAne, Chalfont St Peter, it's a looong time since I was there but still hear good things about the place. 01494872132 http://www.brawlingsfarm.co.uk/ great hacking from there too.
a friend was at Grove farm and i wouldn't personally.
Have hurd good things about Brawlings although never been myself. theres a lot of yards out that way although mine are bovingdon/flaunden so don't know much about them
I used to teach at Brawlings Farm - and have nothing bad to say about the place. The horses were relaxed and happy, staff were friendly and competent, and many of the liveries has been there for donkeys years -always a good sign. Never noticed any politics, and the atmosphere was always lovely.
Liveries have a separate yard to the riding school in most cases, so not affected by busy times, although I suppose that using the school during the day at weekends might be a bit difficult. Nice place.
I don't know grove farm. I know Brawlings a bit as our RC do dressage competitions there and some of the school horse enter. The school horses all look in good condition and happy and I also see them hacking out when I am hacking out. It seems like a friendly place but I have not liveried there.