Thank you Paul, Graham and Morbic people,
Reassuring to know others have been down the same track.
Graham’s design is more or less what I was planning, that is a s/s eyebolt fixed longitudinally through the stem, fixed in a cut out in the central panel, and with a cut to size s/s washer on the inside to spread the load; just above the water line seems the right place. That means that any tow tends to lift the bow, rather than bury it.
I have previously fitted an eye to an Oughted Auk, (see photo) and it tows beautifully.
We are planning an expedition out to Great Barrier, about 22 nm, but across the Colville Channel. And it would be good to take the Morbic if I finish in time.