When I started in the hobby melamine coated wooden enclosures were common. I used Flexwatt heat tape under mine (similar to UTH). The problem is to penetrate the wood and get the desired temp in the enclosure you have to turn it up pretty high. It could be a fire hazard, though I never had a problem. If you could get a radiant heat panel (RHP) it could work. They bolt to the ceiling and heat the air and floor (unless it's a tall cage). The wooden enclosure manufacturers in the US recommend using them in their products. If you don't have them in the UK you may be able to get one shipped. They are not made of any glass or hazardous materials as fa as I know. Forgot one point the UTH or heat tape goes under one side of the bottom of the enclosure, no more than half way.