This is a hypothetical question because - touch wood - it hasn't happened. Thanks for the replies so far, and the information about Lloyds Aviation and Airclaims.
Good point Compressor Stall about same type aircraft having varying tyres and MTOW. They can vary by a few tonnes easily. I would assume that Murphy's law would prevail, and it would be the heaviest aircraft of the type . . . . . .
Unforeseen cascading of events is the big worry. I've been involved in quite a few construction court claims as an expert working for insurers, and I have seen that they can cascade out of all proportion. I have an airport one now, where the original advice cost under EUR 20,000, a taxiway was built, and the taxiway failed soon after due to omissions in the advice. The repair costs will be anything from EUR 100,000 for a limited fix, to over EUR 1 million if the taxiway is to be rebuilt as it should have been. And if it gets to court (too early to say yet), the legal and expert bills will be in the vicinity of EUR 200,000 whatever the judgment is. Not nice for something that started out as a EUR 20,000 problem.