G.I.B.
I'm doing my IMC with the Manchester School of Flying and my lovely wife is doing her PPL there.
Restrictions about the time of day is very much related to the costs involved. Manchester has an unusual (?) system of departure fees and not landing fees.
For light airctaft there is a 'procedure' which involves entering the zone on certain routes then getting to the runway by a different aproach to the airliners which usually involves a diagonal 'base/final' and a nice drop onto the active runway. It seems to fit in very well with commercial traffic but can force a holding at 1'000 for quite a while if you are unlucky.
If you are a GA flyer and you want to try Manchester it is possible to do it 'on the cheap' by using Manchester School of Flying as your handling agent. At the right time of the day you can get in and out for about £40.00.
I must admit that I havn't yet gone in there with my own aircraft yet.