I bought an LD10 body and tail cap for my LD20 so I could go back to using it as a pocket light for the summer months, but the threads were different! The LD10's body threads we're much finer than that of the relatively course threaded LD20's bezel I've emailed Heinnies to see if it's just a one off, but was wondering if any of you had found the same on yours?
You need an LD15 obviously http://www.fenixtorch.co.uk/led_torches/fenix-ld15.html