That's interesting, I didn't know that Simon.
@Ben Butler A lot of people have tried the license free radios and to be honest they aren't very good. They are on UHF at 446MHz btw.
The problem with a lot if not all hand held radios is that the microphone sensitivity is designed for the radio to be held about 8-10 cm away, with a paramotor clattering away directly behind you that is very easily picked up. With a close miked headset pilots tend to shout a little and the resulting speech is often unintelligible. I have reduced the mic sensitivity on all the radios I use.
The 446MHz radios are also in the hands of every Tom, Dick and Harry (read kids) and finding or keeping a free channel is nigh on impossible, as in reality there are only 8 channels.