This pipe goes to the black IGNITION box and just pushes on. Keep this tube clear by blowing down the pipe to the air cleaner NOT INTO THE IGNITION BOX as this will damage the unit. The air filter should have a large diameter woven steel wire re-enforced pipe leading to the front of the engine bay so to get cool air into the unit and is secured to the airbox with a jubilee hose clip.
GoMog is a great source of information and Haynes book manual on the Rover 800 and 820 will be of great help to you regarding the engine.
Great Morgan and our 1990 Morgan has now covered 183,000 miles. Just make sure to change the cam belt at 4 years or 48,000 miles, Looking at your photo I realized you must have a left hand drive car as your windscreen washer is on the other side to ours and the ignition box on our R/H car is beside the windscreen wiper motor. Hope this helps you but I know nothing on L/H plus 4 models or were this box is located.
Kind regards, Dennis. MSCC 7564