After making the morning flatties for myself and Mrs Rob I opened the steam tap on the Giotto Evo for one last cleaning blast. There was a tiny puff of steam and a small click and that was that. Upon investigation the tiny end of the valve rod, which is retained by a small circlip, had broken off. Cue major Google session. BB closed and everyone else I could find it at in the UK out of stock. Eventually ordered from a supplier in Utrecht, Netherlands. We will see how long it takes to arrive.
Meanwhile, a temporary solution occurred to me. Swap the Hot water tap for the steam tap. This can be achieved by simply unscrewing the actuating mechanism from outside the machine. No need to take panels off. Just needs some care with two spanners because they were very tight. Hurrah! We have steam again which should keep the family happy. When the parts turn up I intend to put the hot water tap back where it belongs and replace the steam valve rod.