Jettisoned the idea of a further shelf and went with a mirrored wall cupboard (non-opening). Items that would have lived on the shelf can just as easily live on the cupboard top 🙂
I’ve used a black felt-tip to ink up the outer edge of the ‘wall’ light and added a pull cord to it too. I stood around for ages trying to work out whether to put a door knob on the inside of the airing cupboard but could see no sense in it, though don’t quite know how the shank of a single door know turns the mechanism – hey-ho. Just don’t get shut in there, is all I can say!