Cheers for reply mate, I will be stripping head off after work this evening - I will post some pics.
Do you know if the cylinder liners come out like on some other engines or are they cast into the block, I suspect with the design of this engine that a rebore is the only option with these engines. I have never known a chain slip to cause so much catastrophe on older engines, but then I was last mechanicing in the early 90's and engine design was so different then. Just proves the old saying - 'use it or lose it' and at nearly 50, that rule applies even more.