Common Lizards

Hey guys. I am writing a piece on the health of peoples allotments and wondered if you may be able to help me out. In the winter I found these guys hibernating in my shed and while they are common lizards their numbers along with the slow worm are dwindling.  So I was wondering are people seeing these on their plots and for any long term plot holders have they seen a difference in there numbers?  Also, I know a lot of councils have banned allotments from using carpets and I am not asking you to grass any one up (get it!) are people still using them?  Any replies will be appreciated. Thanks.