ryobi direct not connected directly to ryobi but good prices in general run by cbs powertools
https://www.direct-powertools.co.uk/ryobi-batteries-chargers-c102x2256588
just be aware if you get the latest fast charger and new style batteries they will fit the tools old and new and work but the charger has a list off compatible batteries
and the batteries tell you what tools they are designed to work with that precludes all blue tools and older green tools
now it doesnt say why but i assume protection connected i simply dont know so maybe choose the silvery batteries
just be aware ryobi batteries are more expensive than most trade tools now dewalt for example