Highly recommend Diamond. They service our boiler and water tank every year. Always on time, polite and professional. This year we needed a repair which meant draining the tank. However when the repair was undertaken they discovered they could do it without draining it and told us they would amend the quote! So we paid much less which was nice. They didn’t have to be so honest and could have easily asked for the original amount. Highly recommended by us, we will see you next year!