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.
Good luck
Jeff