Just a heads up from anyone interested - was just in my local Aldi and they have a pallet full of petrol powered water pumps. It looks ike a little generator and can apparantly shift 7900 gallons (not sure if UK or US but was it's in the UK I would guess UK) in an hour for the princly sum of £19.99.
I can't see it on any special buy notices or their website though so it may only be a local thing. Aldi Altrincham certainy have some.