Hello, newbie poster looking for help. I had a gas cooker unplumbed to paint the wall behind it. The engineer took away a piece saying he couldn't leave it legally. I know now that's not true. I have the hose (STRAIGHT BAYONET COOKER HOSE) https://www.screwfix.com/p/cookerflex-straight-bayonet-cooker-hose-12-5mm-x-1200mm/33878 and the angled bayonet socket gas fitting. https://www.screwfix.com/p/angled-bayonet-socket-gas-fitting/32417 Can anyone tell me what piece is missing? Thank you!