Stunning - thanks guys!
I have been doing some trials with various different thermometers in different positions, and had come to the conclusion that there was not an even temperature throughout the incubator. Perhaps more insulation really is all it needs. The heater would then not have to work so hard, but the fan would still be going the same, and that might even up the temperature.
Edit - Mrs Womble has just reminded me that the incubator worked perfectly when we lent it to a friend last summer, who lives in a nice warm modern house. Perhaps it just doesn't like old draughty stone buildings!!
As far as humidity goes, I know what used to work with the manual incubator (just a small pot of water in the bottom - nothing special), so I'll ditch the pump and go with that again. Here's hoping - I have a big batch of indian rubber eggs on their way to me (yes, that was a typo, but I decided just to leave it in
), so
.
Cheers!