You can get the Fenix and TwoFish mounts from Deal Extreme at much lower prices (compared to UK prices anyway). The Fenix mount is quite good, but a pain to remove the light, which you will want to do when you lock the bike to something in a place accessible to the general public.
Something such as the Quark AA2 is small, well made, 200+ lumens OTF, and inexpensive. And it does not die suddenly. There is a graceful 5 minute wheeze, giving you time to stop and replace the batteries.
Something tells me that if you encountered a lion, you would stick your head in its mouth for fun. :huh: