Re: Low level loss of concentration
" I doubt they'd physically see a slow-moving paraglider in time. Hopefully their radar might pick you up,"
The rules are see-and-avoid. If you can't avoid 'cos you're doing 1000mph then, technically, you shouldn't be there. Every so often the Airprox board makes this point, but usually they fudge it.
Practically though the RAF are the main reason why the airlines haven't bribed/lobbied the government into making the entire UK airspace Class D or worse, so don't get too upset about it.