Actually my LED Lenser isn't the police tech model its one of these v2 profesional:
http://www.torchdirect.co.uk/professional-torches/led-lenser-v2-professional.html
The LD20 is twice as bright and lasts 4 times longer on the 2nd mode which is similar in brightness. The Fenix was only £10 more expensive.
My Lenser could have been faulty as other have reported they get much better runtimes, but it's put me off the brand. I don't think AAA are an ideal battery to be using with torches though. The highest capacity ones I could find were a pitiful 900MAH. AA go to 3600MAH, so i don't see how people are getting such long run times with AAA batteries in their Lensers. Mine lasted less than an hour on its only mode which I believe is 60 lumens. That was with a set of 900MAH Energiser rechargeable, then I ended up buying a set of Eneloops and they also lasted less than an hour.