Thank you everyone for your advice.
Yes, I have informed my insurance co. but I don’t know if the other party has done the same, but my insurance co. confirmed that the other party was at least insured (determined from Veh.registration number).
I will present the estimate / quote to the other party and see how I get on.
Any advice on what I should do if the other party dithers when presented with the estimate or does not make payment before the scheduled repair date ?
Thank you again for your suggestions.