Hi,
Actually, regards medical cert, depends which PPL you want!
If it is an NPPL (Microlight), then it is just the NPPL self-cert countersigned by one's GP that is needs as an instructor.
Not sure about NPPL SSEA.
To answr another question:
Where have all the renters gone?
Answer: they have bought aircraft.
Microlights are expensive?
Well, if you have the cash to buy a 50k microlight, you are not the sort of person that wants to pay -in Scotland - in excess of £100 an hour for a cosmetically clapped out old product of the US aviation industry.
If you are the sort of person to spend £2,000 on a third share of a £6k second-hand two-stroke microlight, then you don't have the cash to spend in excess of £100 an hour to rent a cloapped out ...
Of course, there are middle routes, but the arithmetic is all the same. You can afford to look after a microlight/LAA aircraft and polish it without the risk of incurring the wrath of EASA. You can usually sell a few years later for what you have paid.
So low running costs and little depreciation. Low fuel burn. Able to operate out of cheaper facilities than many traditional GA types.
Perhaps the reason the US is cheaper for traditional light aircraft is that every airfield has an A&P mechanic rebuilding a Cessna at the back of a hangar. Their paperwork to get the qualifications and run that sort of operation must be much simpler.