Whilst not happy with the situation, I lived with it, in the hope that it would one day sort itself out without any action needing to be taken and I think Keith was of the same mind, so we kept a watching brief, but occasionally, my clients need to use this lavatory too and I can hardly dart in after they've emerged to lift the cistern lid, not without awkward explanations, anyway.
So, yesterday, Keith was finally on the case and sorted it, by himself, without having to replace the cistern and he is, naturally, very proud, as he has kept on and on about it not ceased to remind me of his success for the past twenty four hours.
That's that, then. Now onto the other items on the to-do list ...