Mike and i are still in love with our bathrooms — and would recommend avon plumbing without hesitation! Want to discuss the right boiler or central heating system for you? call on. Registered with vaillant, i can extend the warranty to and years the price will start from £ for a combi to combi swap i install any type of boiler and full heating system vented and unvented included in price: landlord certificate . Combi boilers: is a combi boiler the right boiler for you? When you need an emergency.