That is 'the' question. I don't have the experience to tell. Was the sheered bolt the cause of the destruction or part of the result of the big end bearing seizing.
On another note, we have found a cafe sport engine 6000 miles on it which has damaged heads (smashed fins) which therefore is slightly cheaper than a couple of higher mileage complete 1100 sport engines, one from a sport corsa.
I thought that the lower mileage engine would be the better as I thought that Harry's heads were ok, but discovered this afternoon that the intake valve has bent. I have yet to remove the right hand head but don't foresee any damage. I am thinking that replacing the bent valve and using the original heads may still be an option. What are your thoughts on this?
I would replace the whole engine. The original heads still could be damaged, although not visible. There's little chance that an engine that has already done several 1000 miles, will break (again).