That was a bloody rigmarole and no mistake.
I took the ladder upstairs so that I could access the loft. No problem initially, but once I have the loft hatch open, the bottom of the ladder is flush against the bannister supports, so it's actually quite a problem getting my Size 13s between the plywood supporting the bannister and the acute angle of the ladder. It's OK on the second step up, but I can't do that in one go.
I took a 4-pint milk container of tap water into the loft with me, thinking it would probably need it, but the bloody tank was bone dry. I tipped it in and called down to Jan for more milk containers full of water. She struggled up the stairs with 4 of them. I knelt just above the loft hatch, applying the Winnie-ther-Pooh philosophy that, having got so far, it seems a pity to waste it. She passed them to me one at a time, using her walking stick handle crooked through the bottles' handles.
But then another issue occurred: I'd been kneeling so long that getting up was a problem. I managed eventually, but I could feel my calves getting into a pre-cramp spasm.
Anyway, I've poured 20 pints of water into the tank. I've left the ladder in place pro tem, and this evening, when it's colder, I'll turn the heating on and see what happens. I expect there will be some radiator bleeding necessary, and then I'll check the tank again.
But I don't know how many more years I'll be able to bugger around climbing up into lofts. Weighing 25kg less would help a lot. It might be time to enrol younger, lither friends to do this for me.