I wanted to see what effect a 74C stat would make, but as might be expected it only really keeps the engine cooler at the start, once the temperature rises after the stat is opened there is no difference to the 82C stat I had in place before.

The brake switch have finally given up and my brake lights have started sticking on intermittently. The brake switch is the original one and was pretty rusty, so it wasn't a surprise it had stopped functioning.