Hi, well, if you have 400 pounds, you can try to find services that can fix your boiler for 400 pounds and not 450; what's the problem? I would sell your boiler and buy a combi boiler because it is much more efficient, and paying for its services is much less than for a conventional boiler. In general, you should read an article about the
pros and cons of combi boilers and conventional boilers [smartboilerrepair.com]. I think you will understand that I am right. However, if you still want to fix your boiler, I can send you several services in private messages. Well, I hope I have helped you.