Finally got started on the workshop. I removed the wood and nails that provided the makeshift storage among the beams, then removed the faulty fluorescent light before treating all the remaining woodwork with a universal wood treatment solution. The walls were then painted with white masonry paint, and the metal beams with green metal paint.
I’m waiting for the floor paint to be delivered, and once that’s done I can think about getting the electrics installed, and fitting a bench and storage.