And a Solution...

The joiner has confessed that he messed up. There should be another step. He was hoping that there was enough length at the top end of the strings to add another step, but on a visit this morning he confirmed what I thought. There isn't.

Instead he is proposing that the top of the strings terminate in some mini newel posts and that these newels are fixed over the joist trimmers. The missing step will be built in-situ. He has also done the right thing and said if we insist on him making the whole thing again, that is what he will do. Apparently it really will be a start-from-scratch thing as everything is glued up. there is no way it can be deconstructed now without causing major damage to the various component parts.

However, Jan and I are pretty happy with his proposed solution. It is not unusual to see the the ends of mini newel post descending from the ceiling under the top of a staircase. My parent's previous house in Devon had them, and our friends in Locks Heath, likewise. Another advantage is that none of the staircase will be visible above floor level, making for cleaner lines behind the glazed partition. As long as it is going to be strong enough, we are happy with this.

He is going to proceed on this basis.