IO540
Ever flown near to the Malverns on a thermic day? or try flying west to east when Popham or Sandown have a microlight day?
For my type of flying, these are the big risks - that and pilots who don't look out the window. This summer I've lost count of the times I have had right of way and have had to change course and put on my landing lights to avoid a dozy pilot who never made the slightest attempt to change course as required under the Rules of the Air.
Obviously I can't know why they didn't see me, but lit up like a Christmas tree I would guess looking out wasn't their prime concern.