Hello Duncan,
First, let me say, I'm not a pilot. However, I have a keen interest in "the scene" and see you are quite low on the learning-curve. You've come toa good place to get a variety of opinions.
Firstly, choice of Aircraft.
By farthe cheapest to own and operate,is the Flexwing Microlight....can be folded down, put on a trailer and parked in your own garage....time to unload and rig, about an hour.
If you are mechanically-inclined, you are permitted to do your own maintenance...at the extreme, the very lightweight single-seaters do not even need annual inspections.....if you're daft enough to want a Darwin Award....the authorities allow youthe choice
Also in the Microlight category, there are two-seat, perfectly conventional "proper" aircraft,which, by nature of stall-speed, wing-loading and weight, , slip below the barrier.....some of these designs are Composite (smooth,curvy, shiny "fibreglass") some are fabric-covered "skeletons"with lightweight rigid floor-panels etc.
Some have a folding- wing design and the same advantages as flexwings, though youmay need to extend the back of the garage, a tad!
DIY maintenance, BMAA Administer.(again, you can pay someone to do it for you, but there are few restrictions.
Like Gliders,you can get trailers that are enclosed....fold the wings, slide her into the "wheeled Crysalis" and padlock the door.
Here, perhaps I should mention Motor Gliders....apart from needing a lot of aerodrome space for takeoff/ landing, they're very cheap to run and maintain.
On to Permit Aircraft...Predominantly homebuilts, but als covers all the light aircraft "orphaned" by the factory and type-certificate-holder withdrawing support. Usually 'cos they went bust!
Permits are administered by LAA -again, you are encouraged to fettle your own, but , however it's done, LAA have oversight...upshot is, you don't need a qualified Aircraft Mechanic or Maintenance-organisation to do your work....a massive cost-saving.
AFAIK, It's perfectly legal to learn on YOUR OWN Permit aircraft, so, you just pay the instructor and the Training-organisation, under who's umbrella youlearn.
Lastly, you have the Certificated (CAA, CofA) aircraft.....the country's training fleet is predominantly"spam-cans" -Cessnas and Pipers....most are older than you and have withstood more use and abuse than both of us! Safe, robust and forgiving, but sophisticated, they ain't. Maintenance is eye-wateringly expensive. All parts have to be approved, all but the very simplest servicing and maintenance-tasks have to be done, signed-for and certified by approved parties.
(IMHO this doesn't make them any safer at all and statistics tend to support this view)
Certificated aircraft can be hired out , used for commercial work, flown in the UK at night. flown in Instrument Meteorological Conditions...which permit aircraft are not allowed....BUT THE COSTS ARE MORE THAN DOUBLE THE PERMIT EQUIVALENT...
In the Certificated category,you'll also find what appear to be MICROLIGHTS...but the engine's bigger, the wing smaller...so,they're faster and heavier,have a bigger payload (you a pie-scoffer?) and cost a massive amount more to run and maintain.
All Certificate aircraft have mandated inspections and maintenance regimes...if you're bored, look up cessna SID'S" Throwing away unused seatbelts and installing fabulously expensive new ones, simply because an arbritarily imposed calendar life has been reached, is not my idea of responsible, ecologically sound or sensible legislation.
Best "bang for the buck?" a Microlight licence willbe the cheapest, quickest way to the freedomof the skies,Unfortunately,
AFAIK, you can't use Microlight-time for PPL/CPL hours-building. The steps to convert to a full PPL should be relatively painless and easy.
A Permit aircraft would be quite a big step, but you
could wind up with your own aircraft
and a PPL for very little more than the cost of conventional Flying-School lessons...then you have a cheap way to build hours!
Splash ~8- 10 thousand and you'll learn at a school, on their plane and they will do all the admin. easy, hassle-free, you get what you pay for.
Me, I'd like a taildragger on Permit it won't happen....but a microlight just might....some 3-axis jobbies do looka bit Heath Robinson(high wing with the engine poked forward on a pole
but cheap as chips to buy and run and there's room for 2!
Well, that's plenty to think about...no doubt someone will be along to correct all my errors and omissions!