Hi again Soggy,
I had to eliminate most of my tomato plants as well a couple of weeks ago.
Yes, the heat and perhaps some wilt brought by white flies. And I now also have spotted some white flies on your previous pics. Be careful with those, they are carrier of many nasty deceases! Watch leaves daily and take measures, quicker than a.s.a.p.
I've got a wild species (native from Northern Thailand) that is very resistant for heat and against all the nasty stuff as well.
If you are interested, write me a PM with your address and I'll send you some
seeds over.
cheers Luches