[acshortt5]

I think you need to divide up what you are looking to achieve.

1) You want to see what the car can do - a track day with an instructor would be the best bet. A course such as Blyton Park would probably be best to start with as it has plenty of run off so you won't bin it if you make an error. A big heavy FWD car with ABS and traction control will be very forgiving.

2) You want to improve your driving technique - again a track day is going to be the best bet where you can practice in a controlled environment. See if any of your friends do track days and try and get yourself added as an extra driver on their car (it's usually only £30 extra) if they will let you. That way you don't bend your own car if you get it wrong...

3) You want to improve your "perception" skills (I call it "the force" - star wars fan) This to a large extent comes purely from experience in my opinion. I suppose you could put in a dash cam and try doing the commentary when driving along (noting speed limits, warning signs, hazards etc) then you can play it back and see if you missed anything. There used to be a short course you could do called "pass plus" which was 6 hours and could get you discount on your insurance if you passed. It was a widely available scheme but I don't know whether it's still available. From memory it's not hugely advanced but is probably the best to start as an initial step up from the driving test before considering more advanced schemes. EDIT - just checked and looks like Pass Plus is still available for circa £150 - £200.

From my experience I would bear in mind that there are 2 different limits: yours and the car.
Your limits for driving mainly come down to reaction time - which clearly can be affected by multiple factors and experience -which you only really gain by giving it a go.
Cars vary in their limits. My mx5 has different limits in terms of handling/braking from the S70 and also in how they feel when driving.