These steering wheels were all made by Grant. The adapter was the make of the donor steering column.
Grant has a plethora of wooden steering wheels and you could even get “banjo” steering wheels. All you need is $$
or your local auto supplier that sells Grant products.
Keep in mind that if you change from the 3 bolt attachment to a Grant Signature series, you’ll have to change adapters.
I tried to post a picture of the one I installed on the Pink MG to replace probably the exact one that you had. I had A GM (Chevette) column, so I bought a billet adpater and a flat, wood Grant Signature wheel that attaches with 5 FHSC (#10×32).