Get yourself down to Dixons with £20.
Get a Uniross Recharger with 4 AA Ni-Mh batteries - do not get Ni-Cd. Usually called "Hi-Drain" or "Photo" Get the higherst mAh rating you can - 1800 mAh or more. Then you'll have loads of power to take pics.
I use 4 AA 1700 mAh Ni-Mh in my Fuji S304 and they take 200 or so photos with flash before showing low battery.