Thanks guys. The head was retorqued twice after a few runs but I have some doubts as to how reliable the borrowed torque wrench was. It seemed a bit dodgy to me but I was assured that it was behaving normally. I'll get my hands on a different one this time.
Cheers for the heads up on annealling. Despite searching and reading far and wide on top end rebuilds I'm surprised I never came across this process. I think when I get the gasket in the post I will anneal it and use some of the copper spray before installation. Just to be sure.
While I have the head off I figured I'd attempt to paint the tank. It seemed to be growing rust quite quickly. As you you can see it is quite rusty but the surface is smoothed. So far I have only stripped it. Anyone recommend using rust convertor on here? Any other prep ideas before I prime?