In the 'worst ' case, you can use the old lid to make a mold for a new hatch. A fiberglass shop could do that.
If you are not too picky, a hatch could be fabricated using Starbioard. The color probably won't match but that approach would be a lot less expensive than having a mold and a lid made.
The old lid may be repairable. Bring it to a fiberglass shop and see what they think.
I blew mine up earlier this year. Tore it up with windlass. To save my Florida trip I made one out of 3/4" plywood and sealed it with a layer of fiberglass cloth and resin. Worked fine.
In the meantime, the plywood coring in the old one is torn up and difficult to remove. It's not repairable for on-the-water use but it will make a good model for a mold. I'm in the process or patching it up. At that point I'll make a new one. Mine is 29 1/8" x 9 3/4". Not sure if GW used different hatch sizes across models.