Mapdec sell the same lights as mtbbatteries but for less (they haven’t been rebranded).
Halfords are doing the Gemini Olympia for £150
http://www.halfords.com/cycling/accessories/lights-reflectors/gemini-lights-olympia-1800-lumen-light-system-4-cell
It was £140 a couple of weeks ago when I got one via Cyclescheme. Although I says 1800, I received the newer 2100 lumen (alleged!) version. Note that it comes with the soft pouch battery not the hard case on as shown. On speaking to i-ride, it appears that Halfords order direct from them when an order is placed, and have just not updated their website.
It’s an awesome light.