Just in case you're not aware, Ay Up are upgrading existing light sets (100 customers a week). Sent mine off a week ago and they were returned yesterday with new LEDs, upgraded resistors and new all-round lenses. I'm not totally sure of the output but it must be around 1200 lumens for the double set. So far only had a play in the garden but very impressed with the brightness and spread of light. In fact, I would seriously wonder why you would need anything brighter for night time riding.

[Mod. moved to Geek Gear]