Awesome that you're building your own viv for your Yemen. I am not sure what temperature you are able to maintain during the day, but nightly temperature drops are a positive action in a well put together set-up. I don't know what temperature you're working with in the U.K., but a nightly drop to 60-65 degrees is just fine for this particular species. I like to keep my Veileds' on the higher end of that spectrum myself. I live in Texas, so needless to say, it's not a difficult task keeping nightly temperatures where they should be. The only other thing I would suggest, is that the more ventilation you add to the enclosure, the better overall health you will see in the animal. I hope the viv turns out great!
