Thanks everyone for all your replies thus far. It's both confirmed a lot of what I've been thinking, and given me a couple more options to consider.
The Panda has been amazing. Low cost investment and cheap as chips to insure and tax.
Mine too, basically the same story. Pretty much everything on it is original; I've replaced two sets of tyres, three sets of wiper blades, the thermostat, battery, exhaust, droplinks and rear shocks, but the rest of it is as it left the factory.
But 115,000+ miles means there are a lot of end of life parts that really do need replacing now. The clutch is on the way out, probably needs new hydraulics and an input bearing too, front seats are threadbare, it needs another set of tyres, a battery, probably most of the front suspension, sump & twist beam are definitely past their best, the digital part of the display is intermittent, the power steering occasionally cuts out, and Ladykitching won't drive it anymore in case it throws a wobbly. At least £1000 in parts, just for the immediate stuff, at least a week's work; and it'll still be an end of life car that could fail outright at any time; I'm in the fortunate position of being able to afford better and it's time to move on.
I know whatever I replace it with is going to cost several multiples of what it's cost to run the Panda, but life is just too short to spend any more of it on keeping this car going. And Ladykitching would be VERY unhappy if it was still here at the end of summer.
For the last forty years, I've adopted a strategy of buying new, doing all my own maintenance, and keeping to end of life. That's probably no longer realistic; I think now I'm going to have to fundamentally rethink my attitude to car ownership.
I don't do a lot of long journeys now, indeed, I don't do that many miles, period. And secondhand EV prices haven't held up too well, making them look... ... interesting?? But that's a sea change in thinking; not sure I can get my head around it.