Hi Tom .
been diving for one season in uk waters now looking forward to my second year of the east coast north sea . i have a reletivly inexpensive TEC LITE about a £100 very good for my needs , looking into holes and stuff around wrecks during the day its fine and at nite more than ok .One of the guys in our club i dived with a week or 2 ago in a lake in about 4m vis ;his torch is high maint cost him about £800 ish and is not that much better . Good luck . i am told the northern diver is red torch is good too. i can only say the best thing is to ask as you are and read lots and lots of reviews.