Long established company under different names, LithiumPowerInc, Boston Power in the U.S. Regional distributor Europehttp://www.anewpow.com/
Supplied Roomba batteries for many years. High quality with warranty. Well regarded. Makes batteries for medical equipment.
They may also be sold under Private Labels by other dealers, as on AliExpress.
A new item is a battery for Botvac now in testing at dealers.
They may be cheaper without the filter packaged.
These batteries are direct replacements for NiMh, with no special settings used in Neato software. Adapter circuitry is included for lithium.
Tenergy is also a well regarded brand and has similar batteries. Possibly private label from AnewPow/LithiumPowerInc.
Sold at major battery dealers, online, etc.