Dealership taking 5 weeks to repair car leading to missing a holiday

Audi have had my car in for a warranty repair for 5 weeks. It took 3 weeks for them to even begin work. Then they had to order parts which took another 8 days

They have not provided me with a loan vehicle in this time

I have a holiday to Europe via euro tunnel on Wednesday 15th of July. I won’t have my car back before then

My options are

1. to not go on the holiday and lose £1500
2. book a rental car for 10 days at a further cost of £800

To say I am angry at the whole experience is putting it mildly but I am trying to keep my cool. Is there any angle I could approach for some form of compensation?