We took our horse lorry to a local garage/ mechanic to be checked and taken for it's MOT. The mechanic has been hopeless - he's had it for over 2 months, totally screwed up on the repairs and it's all cost us £2000 but nevertheless it now has it's MOT . The mechanic has been difficult to get hold of/not returning calls or answering messages all the time he's had it. He wouldn't let us pick it up until we'd paid the bill (fair enough) so we paid by bank transfer and our friend went to pick it up yesterday.
On picking it up our friend noticed that the bodywork has been badly damaged at the back. It's clearly been crashed into something or something else has crashed into it. There are two holes in the bodywork 
and the metallic trim/edge of the bodywork has been knocked off and he's crudely screwed it back on (with screws which are in a different colour and in a different place so quite obvious!). The mechanic hasn't mentioned this to us at all and conveniently had left to go on holiday 5 minutes before our friend arrived to pick it up. Our friend took photos on his phone before he removed the lorry, but he had to take it as it's needed this weekend. We plan to get some quotes for repair and ask the mechanic to pay for the repair (when he eventually gets back from holiday) but knowing his previous behaviour it's likely he will ignore our calls/be absent when we visit/deny all knowledge.
What should we do and how should we proceed?
If anyone wants to knwo the garage so they can avoid it (it's in South Lincolnshire near Grantham/Stamford) then please PM me.
Thanks all.