Additional third solution to bent valves
Search for mobile mechanics in your area, (at least two) on social media/google. Search their trading name for adverse customer reviews/customer recommendations and ccjs on review sites.
Inform them that you want to become a long-term maintenance and repairs customer, increases the chances of getting a good job done.
Ask them to quote a fixed price to supply and fit good second-hand cylinder head, new gaskets and cam belt. (Approximate price £250 for cash). You pay your money and take your chances with this cheaper option, however you may consider it worthwhile?
Good luck!