Fenix do a good range of quality LED torches.
I would look for a head lamp rather than a hand held torch or a least a torch small enough to hold in your mouth for those fiddly two handed jobs.
Find it very handy when I go to remote location early in the morning.Can't help with the torch, but an alternative to bin liners, if you are just sitting (rather than lying) on the ground, is a bum mat. They are small pieces of the closed cell foam used for sleeping mats. They provide more comfort if the ground is rough and better insulation.
Dave
These are cracking torches:
http://www.amazon.co.uk/Lenser-Police-Focus-Torch-Black/dp/B000OGCP6W
But the LED Lenser range as above is the current choice for professionals of all trades.