I contacted John (Full Flame) because of the positive feedback I found online. I am always very careful when it comes to hiring a handyman or engineer as unfortunately there are so many bad ones out there. John arrived on time and was very (!!!) thorough and friendly. He was able to explain to me everything he did when I asked him, which is always a good sign as this shows that he really knows what he is doing, and he fixed the problem. He did not try to sell me any unneccessary things and even checked if my boiler was safe in terms of carbon monoxide emission and bled my radiators (and explained to me how to do that myself in the future). After he finished fixing the boiler he stayed for 5 more minutes and tried all kinds of settings to make sure the problem was really fixed! I was very happy with his work and can and will absolutely recommend him to anyone who is having trouble with their boiler!