but it's obvious from any actual flying around the UK that almost all non-transponding targets are flying at very low levels; typically under 1500ft.
I doubt if many on the 2,000 gliders in the UK spend much time below 1,500' on cross country flights. Mostly we spend our time around cloud base down to approx 1/2 the height of cloud base, normally 3,000' + Also gliders are frequently above 10,000' when wave soaring sometimes at FL195 and exceptionally in the mid 20,000' to 30,000' levels.
Cross country Glider flights are typically 3-5 hours long and sometimes 10 or more. This makes gliding a significant part of the total aviation picture. 200 movements per hour is achieved from Lasham so watch out if these Olympic airspace restrictions funnel all GA into small volumes of airspace. Transiting past lasham will be more than interesting
bb