Thank you everyone for your comments.
I think a mast travel length of 51cm is the absolute limit for my large rucksack even when put inside diagonally (the budget airlines in the UK are very keen to make lots of passengers queuing at the departure gate check their carry-on bags into the hold, and I don’t want a conspicuous pole sticking out the top!). So, based on what many of you said, I’ll try the SOTAbeams mini poles.
Richard (G3CWI) just replied to my SOTAbeams website query and suggested the EFHW would be better than the linked dipole. But, given your shared experiences, I will experiment with both.
I’m keen to try SOTA on 60m and think the lower height isn’t a problem for NVIS activations and my KX2’s ATU (normally bypassed) gives good VSWR using the 40m setting on the linked dipole.
73, Andy (G8CPZ/M0ALC)