To give the seller the benefit of the doubt, he/she might not know there's been damage (just buying/selling on items ?) or they may consider that whatever the damage it's recoverable. The problem comes when they've got more optimism than practical knowledge !
Until TC heads came back on the market over here, it was amazing what folks did to recover an old head. I've seen photos of combustion chambers and waterways which have been completely covered in weld metal to be machined back. Skimming the head face isn't that tricky but restoring the shape of a combustion chamber does sound challenging. But back then, with no new castings around many folks just had to pay up.
But that's for a TC head, for the Renault head I've no idea if similar sums apply. It sounds from your machine shop that the cost wouldn't be economic, perhaps they think the welding/machining is going to come in at more than the head sells for ?
Personally I'd be tempted to at least go back to the seller and see what they say.
Brian
