Not one worth his coin. Gas Safe are purging illegal Gas Work. I find it incredible that an Engineer would do the work and not register it. It will put him in contravention of Building regs and Gas Safe will take a very dim view. You the house holder have the responsibility to ensure that workmen are qualified. If he wasn't you must report him. My advice is to get the Engineer back or contact gas safe for advice.
Projects that add value to your home - Phil Spencer
Looking to extend your home but don't know where to start? Property expert and Rated People ambassador, Phil Spencer, shares some thoughts on why loft conversions are such a popular way to create more living space and add value to your home.