Supplementary question.. can I rock up at my local airfield and fill a few jerry cans with avgas for the bikes?
If your 'local' airfield was Perranporth, then certainly! We sell AVGAS to the local vintage bike enthusiasts, no problem, we simply mark the receipt 'sold in cans' rather than an aircraft registration. I'm sure you'll find a more local airfield who will do the same.
Cheers,
TOO