A mat on the ceiling wouldn't really do that much as most of the heat would just rise upwards. If you're worried about the cold UK winternights get a day/night stat for the heat lamp, these work on timers and reduce the temp of the bulb during the night to a desired value.
1.0.0 Dumerils Boa (Khan)
1.1.0 Corns (Snow Coral Motley 'Jonesy' & Carolina het Am,An,Hyp,Mot 'Indy')
0.0.2 Crested Gecko (Billy The Kid & Jesse James)
0.1.0 Bearded Dragon (Missy)
1.0.0 Leopard Gecko (Derick)
0.1.0 Homo sapiens (Nicole)