If you have to make mistakes to learn, as they say, then I'm learning. I'm almost too embarrassed to post these images, but it does show that I've learnt I must be more careful cutting the stringers. Exactly how I came to make such a mess, I'm not sure. I don't think it was impatience to get on with epoxying. Rather, working with the stringers is pretty difficult as they try and spring back while I'm squashed in a corner under a shelf. Hopefully much of this can be disguised with epoxy later. The stem from starboard. I've started to shape this side. I think the upper stringer is more successful – set back from the projecting middle sheet of the three that make up the stem.
And from port. Again the upper stringer is better. Perhaps I was worried about breaking the lower stringer. Incidentally the stringers are thinner than specified – though JohnW did say it was ok. After seeing these photos John Welsford (the designer) said:
That looks fine to me Osbert. As long as the stringer ends can be planed to be in line with the stem, and will stay where they are supposed to be until the planking is all glued in place then they are not going to be a problem. Remember, “The mistake that cant be fixed with epoxy and some fiberglass cloth or pieces of plywood has not been born yet” JohnW
So that's good news!