Thanks Lee. At the moment it's just idle curiosity though I was also a little worried that you were doing a Flarm and going "closed"!
Actually I do have one question, though maybe it needs a new thread. With the unsurprising emergence of ground stations for tracking purposes, I did wonder if the protocol provides for a "do not track" flag, as does Flarm. Although I am not a fan of Flarm's closed model, they have ended up doing many things quite well, including this. Also, I suspect if you have ambitions outside the UK, you may need to provide this facility (I believe Flarm were compelled to adopt it rather doing it on their own initiative). Since Flarm has a mandatory periodic firmware update this was quite easy for them to do, but as Pilotaware has (I believe) no firmware lifecycle, then it might be better to provide for it sooner rather than later.
Alan