I was thinking of getting rechargeables D cells but generally rechargeables are only 1.2 volts and it would be an expensive outlay at least £45 for a kit.
As anybody used one of these or similar? http://www.qvcuk.com/ukqic/qvcapp.aspx/view.2/app.detail/params.item.500... it Refreshes? alkaline throw aways batteries up to 75% of original power up to ten times. seems the cheapest option at about £20 and good for recycling.