I am in the UK as well and use exoterra tanks I ve got a few pacs all different species. find that with the 30x30x30 I need a mat that covers the entire side of the tank then I ovehat with some foil insulation from b&q that. you also have to cover 3/4 of the meshing on the top with something I use polycarbonate twin wall also from b&q. this kees the temps where they need to be. hope that helps.