Do you have a slow cooker? I proved pizza dough in mine on a low setting (let it warm up for ten mins first) and it worked so well, I was amazed and pleased because I generally don't get on with my SC and it needs to earn its keep
The sugar reacts with the yeast i believe, but if you can taste it, are you putting too much in? 1tsp goes in ours and i can't taste it at all.
I put pizza dough into my gas oven to prove at the lowest setting, ie less than gas mark 1. I've also put it next to a radiator in the past. Or you could heat up your oven, then turn it off for proving.
Do I have to put sugar in? Is it important for making things rise etc? I haven't done much experimenting yet <slave to the instructions> - too scared
Also - I made a pizza dough which worked quite well but it said to leave it somewhere at 40 degrees to prove and I couldn't think of anywhere . What/where might be a good place? We don't have an airing cupboard. Should I put it in a very cool oven?