Hi AHMC,
I did my night rating recently at Almat Flying Club at Coventry. James Green was my instructor and, whilst I can't speak for him, found him very flexible about flying late into the night. They have a beautiful Warrior III, and I did the rating over a Friday and Saturday night. We did a nav across to Cardiff on the night of the lunar eclipse; I can tell you that watching the eclipsed moon at FL60 over the Beacons was something to remember!
I don't know what restrictions there are on, say, circuits at Coventry at midnight though. Glynn Matthews' number is on the website; might be worth a call to see if they can accommodate you.
Best of luck,
waterpau