Low Level Common Frequency, LLCF, was not set up by the CAA, but initiated by both the RAF and GA users in Northern Scotland. The two parties lobbied the CAA for approval for its use, and a 6 month trial has been granted.
Every UK based military aviator is to use LLCF when flying in the appropriate area, and foreign military aircraft are also briefed on its use before they fly in the area too.
Virtually every commercial pilot, military pilot, coast guard pilot and local based GA pilot uses 135.475 every time they go fly in the Highlands now when they can't get a Basic Service from an ATC/ATS facility, so if you're flying up here and not using it, you're very much in the minority and will be very much on your own! I hear Typhoons or Tornadoes making calls on VHF 135.475 MHz just about every time I'm out flying in the middle of nowhere - it doesn't by any means make the frequency cluttered, in fact far from it, there's hardly anyone up here so when you do hear a voice, it can be quite reassuring that in times of need you might be able to talk to someone.
This is not a kid’s game, this is professional aviation trying to make it safer for all who use the airspace, GA included, so please take it seriously.
Low Level Common Frequency use in Scotland is not a cure all for avoiding an Airprox. It is, however, if used correctly, another string to one's bow that may prevent a near miss or a mid air involving you and another aviator, or perhaps afford you the opportunity for a useful weather report as you fly into dreich weather.
BTW Nay Sayers, it has already been used successfully to avoid potential conflict on at least one occasion between a military fast jet and a civilian aircraft since it started in February - that alone had made LLCF worthwhile.
135.475 is omni-directional and potentially has a lot further range than your eyes do. “Hear and Avoid" now compliments "See and Avoid”. Don't use it at your own peril...!
FYI, you might as well use it, you can't talk to anyone else, so what's the point of not using it...? I wish I had had the availability to use Hear and Avoid before my Airprox with a Hawk as he came blasting over a shallow ridge extremely low level and had literally 1 second to avoid him:
http://www.airproxboard.org.uk/docs/423/2014120.pdf
It's interesting reading! Did you know there were well over 200 Airprox reports last year in the UK alone?