Seconded. I've a pair of these working faultlessly 24/7 (they're never without batteries in them) since 2006. Also, if you phone him up, the guy at Batterylogic (it's a one man outfit) will talk to you all day about batteries as they are his passion.
This one, recommended
https://www.batterylogic.co.uk/technoline-bl700n-battery-charger.asp