I can''t specifically remember the hatch on Morgans of that era but it seems to me Morgan was still using molded fiberglass hatches. If the old hatch in in decent shape it is not that hard to use it to make a mold and then mold a new hatch. Morgan used hatches for a little while that were plexiglass in a wood frame, which is also easy to replace. Lastly Morgan also used Bomar type hatch on some of their boats. While the design of hatches have changed over the years, you should be able to find a new hatch from a respectable manufacturer that would fit the "flat" for the Bomar.
It would help if you descibed the construction of the old hatch, i.e. molded fiberglass, plexi in alum frame etc.
Thanks for the information. Unfortunately, the old hatch is gone, so I can''t repair it or use it to make or mold a new one. If I can''t come up with a used hatch I may just make a wood/plexiglass one.