Fuji, will you make use any of the ideas I've suggested that you can do right now to make your flying safer? Without having to wait for the outcome of writing to the CAA/EASA? If not, why not?
The BGA can write to TRIG (or whoever or indeed all transponder makers) but I doubt that anything suitable will be forthcoming for some time to come. In the meantime, things are what they are. You might as well do what you can now to reduce your risks.
Pace, waiting for the BGA to add Flarm to it's laws & rules is prevaricating with your safety. For all you know the glider you had your scare with might have had one fitted - if you had had one then your incident wouldn't have happened. Also, what would be the point of a glider in Scotland giving London details of where it is? *if* they should be talking to anyone it would be Scottish Information, but not all glider pilots have an RT licence and
AFAIK in those without should not talk to ATC except in an emergency. And maybe when your report comes up in CHIRP you'd care to post the URL so we can all benefit? Ditto if it goes through the AirProx process. BTW surely you are unusual in that 80% of your flights are in IMC?