IO and Rod
I think there are a few issues at work.
I commented earlier on a recent trip to the West Country.
In both directions it would have been difficult or impossible to fly at altitude without an instrument rating. This summer such conditions have been a common feature of the weather. To remain "VFR" (and even then not strickly legal) you might have weaved around the cloud or found a route on top but even then without an instrument rating a route down was far from assured.
I think this means that had the viz been 10K with a base well above GA levels there might have been more of a mix of traffic but the fact of the matter is there wasnt and that seems to be typical of any number of trips this year.
For that reason I think LAA types will often be "held down" by the weather but when the weather is good we will increasingly see their numbers grow at higher levels.
In my view there is no doubt the percentage of faster traffic has grown. As you say LAA types are flying at speeds that were never obtainable not that many years ago and there are more fast singles around.
To nail my colours to the mast I dont believe see and avoid works - or should I have said works sufficiently well enough of the time. The faster the traffic the more this becomes true.
It leaves me wondering if we are not going to mandate the carriage of transponders for all traffic we should mandate its carriage for traffic flying above a certain speed or above a certain altitude (regardless of the class of airspace). At least that would mean in the second instance we could be assured that en route above a certain altitude we were no longer totally reliant on see and avoid.
I remember many years ago coming across a hang glider at just over 5,000 feet. Given that the terrain was at most 700 feet I never expected to see him there (all his mates were at least 2,000 feet below). He was legal and he was entitled to be there. Perhaps I should even have expected to come across him. However, despite his slow speed he presented a very poor target - I hasten to add we never the less managed to avoid each other!
I appreciate this may not suite the gliding community or some paraponting and hang gliding sites but how much of this traffic is en route? NOTAMing or establish "danger areas" around sites with non transponding traffic operating above the transponder base might help accomodate all.