Li-ion. Can recommend the 2Ah ones, I have a few from previous kits that charge fast and last a long time. eBay knockoffs available too at a cheaper rate but not tried any as of yet.
Are those Nicad batteries?
No they aren't. They are both part of the Kingfisher Group.
I'd often agree - I never shop at B&Q unless there's something specific only they stock, however they're one of the only stores that sell Ryobi along with homebase. (Screwfix don't), so typically online is the only choice
One gripe with Ryobi, hard to find comparisons between all the different models to see which is the newest and to compare features.