Can I make a suggestion - probably a very silly one as I have no knowledge on this matter - but I plan to look into it...
An airbed pump, e.g.:
Hi Gear Compact Tornado Airbed Pump | GO Outdoors
at less than £7
and if necessary - adaptors, such as:
BRAVO DINGHY PUMP NOZZLE SET | eBay UK
for under £3
would that not give you a 12v pump system for under a tenner?!
why spend so much on the bravos?
I have a battery version of the pump, so might try it...
Alasdair