Cheers for the replies
They havent had time to get it opened up yet but I did tell them to go ahead with it.
As youve said, getting a 2nd hand engine is a risky business as it could be a dog, but also could be perfectly fine.
But i cant afford the risk haha, so id be aswell pay the extra to get it sorted and hopefully be better off.
Ill put an update once ive heard about the damage