Simon
I have fitted a Selden one to a P31, bolting on a Selden ring to the bow fitting, with a deck eye further back to fix the bowsprit. Bowsprit clipped to toe rail when not in use. Worth considering.
Also friend of mine has had one fabricated in s/s and fixed to his stem head,(larger Beneteau) which is a neat arrangement, worth talking to your local s/s fabricator, especially if can make it removable.
Hope this helps
Chris
P31 No 5
Christopher Day
P31/5 Sula