Unfortunately not for the next couple of weekends....
I have a shooting competition this weekend and then from the 4th to the 11th we are on holibobs - I may give it a go on Thursday or Friday lunchtime next week, but time is a luxury at the moment which sucks as I just want to get the head off so I know where I stand with the engine - has a liner slipped?, is the ticking elsewhere?, is the block scrap?, is it worth rebuilding with fresh cam, followers, rockers, rods, valve seals, etc etc?.....it is the not knowing that is annoying me - once I know what is what I can move forward, at the moment I am in limbo.
First order of business is to get some Irwin sockets, and a then with
@jamesmartin 's method of beating it then seeing if it turns, then beat it some more and see what transpires...then failing any movement from there is to drill the heads off!
I have heard of the beating method before to loosen head bolts, it shcoks the threads and they jump and loosen slightly and then you can spin them out. it is the same principle as an impact gun.