The above thread mentions STS low profiles, research will show that no one flys on them because there is no perif vision with them on. If you have a tube failure or strong white light closes them down you are blind.
The best solution is Anvis 9 series, with a Gen 3 Omni 4 tube, they have all the bells and whistles and have been selected by virtually all flying forces around the world except our own! (Not manufactured by UK voters?)
The Police using Fens Gen 2 are doing so because they were sold them in an industry 'off-load' If you think Gen 3 are too sensitive against gen 2 then top marks to that Salesman from Fenns!
Anvis are sold by ITT and Litton, there is a free seminar/sales show in London October 02, Shepard press are doing the NIGHT Vision thing again. Good place to go if you are interested in joining the 'Fly safer at night' brigade. You won't find the CAA there in any number as they seem to object to the use of.
The conference in London is free to view the trade stands but costs to listen to the industry talks, worth it if you are about to shell out the cost of a Sports car on the concept.
http://www.nightvision2002.com/