I just moved in a new property and have met 3 gas engineers in a single week - a moody National Grid representative, a don't-know-anything-ask-your-landlord engineer who came twice to connect our household to gas supply, because the first time he apparently messed something up, and then there was Jessie who came to install our gas oven. He was an example of what an engineer should be, friendly, explaining everything he was doing and what additional measures we should take, for example, buying a CO detector. I'd recommend him to everyone.