Called S I Gas Service & Repair to fix a faulty boiler timer. Engineer was very knowledgeable, and was able to identify the boiler type, and part required over the phone just by me reading the boiler serial number! Phoned to let me know when he was 30 minutes away, and arrived on time. The engineer did not only replace the part, he also took the time to explain how to use the new timer, in addition to also setting it for me and carrying out safety checks. On top of that, the engineer also explained how to adjust the boiler pressure, and having identified that the boiler did not have a key, he also gave me a spare from his van. Very professional service, at a reasonable price, from a genuinely nice guy with vast knowledge from his time working at British Gas. Highly recommended.