Yes, I'd considered a squirt of isopropanol plus naked flame as an explosive solution to the problem, but
thought better of it chickened out.
Wild32, that is one well equipped garage you have there!
Fortunately I managed to collar my neighbour this afternoon, he has every power tool known to man and loaned me his compressor.
I also discovered that my failure at Sainsbury's may have been my own fault. I'd removed the valve core to get a less obstructed inlet… turns out that the inflator tip doesn't let the air flow without the valve core there to push against.