Cheers everyone. I got the heat shield off, impact wrench and bolt extractors.
Also got the seized oxygen senor out, in the end I cut the wires and used a deep 22mm socket on the impact wrench, that's the only way it was coming out.
Now I've get the cam cover gasket to do, just ordered one and some sealant. Wish me luck!
Getting closer to it being cam belt time with every MOT job that's done.
Had the sill welded the other day, was cheaper than I could buy the equipment so all good.