I don’t see a problem if you work on your own installation at home, being an aeronautical engineer. I am glad though that I don’t live next door to you so when the joint does go bang, I won’t get hurt. Look at it from the other side. Would you get into a plane that was serviced by a heating engineer? In other words: do you feel it is worth risking your life, possibly your wife, children and neighbours for the sake of a few hundred quid? Kev was sort of right by the way, it was legal to do your own work at home but not anymore since the 2005 amendments of the building regs.