So I was muttering about this as I packed, and then it struck me, just order a pair of crutches and leave them up there. So I did, and Amazon delivered them a couple of days after I arrived, in plenty of time to let us do stuff together over the Easter Bank Holiday. I was pleasantly surprised by the price, and that I managed to find the same pair that I used for years, and which have the most comfortable handgrips of any I tried. In fact I think I paid less for them this time than I did back in the 90s! By my reckoning that's six pairs of crutches or sticks I now own, though half of those are in the back of a cupboard or in the loft as just too uncomfortable to use.
If you're ever in need of a pair of crutches, I definitely recommend these: https://www.amazon.co.uk/gp/product/