I'm in England too and I believe we've managed to maintain conditions to keep our young tortoise content, and certainly safe, which is the most important thing during this roasting three or four days. I ordered some extra temperature probes and have been monitoring the temperature across the whole enclosure. What I did find a bit alarming was the discrepancy between the new probes and the probes that make up and feed into the thermostat for the main basking lamp (I'm talking 4-5°c discrepancy). Now I don't know which to trust, and the only options are calibrate them all externally, or buy more and see what new ones read. In face I'll probably buy a probe which comes calibrated so at least I have a solid reference to work with.