Microlights can be rented and the modern 3 axis ones are definitely worth looking at as an economical alternative to GA aircraft.
There is a route from NPPL (M) to GA if you decide to continue that way for night/IR more passengers etc.
Lessons are around £100/hr with min only 25 hours so you're likely to get qualified in more like 12-18 months on your budget if all goes well.
Lots of info on
British Microlight Aircraft Association,Home (the forum is useful)
and endless friendly advice on
Microlight Forum join and start asking questions, newbies welcome.