I agree with previous posts. I would also suggest you have a trial flight in a flexwing - they're like motorbikes in three dimensions. A C150 or PA28 feels quite unresponsive in comparison.
As Flystimulator says, whilst hiring microlights is legal, hardly any schools/clubs are offering their aircraft out on hire yet. When you consider that the entry point for a used aircraft (3 axis or flex wing) is around £3k it's not surprising.
Budget on £25/hr operating costs for your own microlight. Microlights can operate from the shortest farm strip and most microlights can be de-rigged onto a trailer and stored at home.
NPPL(M) medical requirement is a declaration countersigned by your doctor - he/she signs to say that you meet the requirements necessary for driving a HGV, so no physical examination.
If you want to fly for fun, go for it. Only drawback with microlights is that your hours don't count towards PPL, ATPL, etc. so if you don't intend flying as a career (apart from being a microlight instructor) microlighting is fantastic value.
Springers