CPX - I dont think Carlisle tortoises should be promoted on a tortoise site - for people who join a site like this who are potentially looking at purchasing a tortoise they 'might' think that Carlisle tortoises are an acceptable place to purchase a tortoise - and we all know they are not.
As Tamie and Julie have both said... heat mats should not be used for a tortoise to sit on.... if used at all they should be above the tortoise - think of a heat lamp - the heat is above the tortoise not underneath it.