Here is the promised photo of the Morse control, looking from the back. At the top you can see the two metal clips, the right-hand one of which had slipped down to prevent the lever moving beyond the tickover position.
Another repair job was to get my bike sorted out. It had lain unused for months with a flat back tyre. My tardiness in getting round to fixing it was because I had thought that the hub gear cable would need to be removed before I could get the wheel off. In the end I found that not to be necessary, and I successfully replaced both the inner tube and the outer tyre. The old inner tube had 16 repair patches!
I'm hoping to organise a similar meal out in two or three days, to a curry house.