Tony
There are 2 basic patterns of TR tubular manifold that do fit the +4
The first was made originally by Derrington and all 4 primary pipes join before going through the hole in the chassis to the silencer
The second , and by far the most popular, has the 1 and 4 joining , and 2 and 3 joining, and then the secondary pipes coming down the side of the engine , through the chassis and joining in a Y piece before the silencer . This is sometimes known a Lawrence(tune) manifold.
Most Morgan dealers involved in racing classic +4s will know where to source them , try Techniques , BHM , Peter Mulberry/Mogsport, JB Engineering to name but 4.
