No offence mate, but a conservatory is a really stupid place to put animals, of any kind. During the day, especially the summer months they get boiling hot, and at night the temperatures plummet. Considering the whole thing is made of glass, all of that direct sunlight on the viv is literally going to cook him. I'd recommend moving him, and any other animals you may have in there, straight out.
85F is fine for a cool side/ambient temp, but he needs a basking spot of 105F. Trust me, if his viv is in a conservatory in London in February, you can bet that his viv will not be 85F, not with a conventional heating bulb/ceramic heater.