Evening Mike,

I am not a legal expert but I always explain to a customer of risks involved before tackling a job such as this. I would give them a price and the risks involved which could impact on the price before going out to the job. The problem you appear to have is that you agreed a set price for the job before explaining the risks and extra costs that could be involved. I figure that the only thing you can do now is get the customers permission to undertake the remainder of the job but if a breakage occurs then it is down to him. If he does not agree, then back off gracefully with a lesson learnt.

Regards

Pete M