I managed to change the gasket and all the studs and nuts, I got the engine red hot first then undid all the nuts, some where quite tight and the first quarter turn was a bit hairy as I didn’t know if any where going to shear, most nuts came out with the stud, only the previous snapped one and one other left the stud in.

the kit from Anembo was spot on, inserting the studs with a hex bit made it so much easier, and as you can see the gasket was toast, I’ve torqued them up to 24nm and I’ll keep an eye on them, hopefully they should stay put now.