Humaround,
You ARE allowed to be taught solo - to fly a microlight!
Yes, it is on the syllabus.
It is a hang-over from the early days where people strapped small engines on to hang-gliders, so - to be fair - they often used to know how to fly the hang-glider first.
But you can still do it now. And you can even do you GST solo too! (although you have to get a dispensation for that now).
Hang-gliding, when I learnt, was also taught solo. It may be now that many people learn dual thanks to aero-tows.
(Learning solo is probably why, going back in the mists of time, that there is still no requirement for dual hours for licences!)