Do you want track or road training ?- they are a million miles apart.
For fast road driving / advanced training then give John Cave a call at Drivetrain
www.drivetrain.co.uk The best day i've had out in a car, excellent training if exhausting, and good value for money at under £300. John also occassionally organises days at Prodrive proving ground for a mixture of pseudo track, road and skid control on the watered sections. Its the best aoptional extra you can buy for your car !
There are other places too such as Cadence who operate road driving skills - the back of Evo magazine has plenty of adverts.
You also need to consider whether you want to pursue Rospa driver ratings - some fast road courses work to Rospa, others not so much (Rospa are more strict about how much of the road you can utilise for instance)
There's lots of local IAM groups, using police instructors as examiners but approved drivers for tuition (you arrange your own 'lessons' on a hour/2 hour basis.
Also buy yourself a copy of the 'Roadcraft' - advancedpolice drivers handbook, available form most book shops/Amazon - it gives the most conprehensive but concise explanation of advanced road driving.
http://www.amazon.co.uk/Roadcraft-Great-Britain-Home-Office/dp/0113408587 For track driving then most major circuits have some form of driving school, and there is a lso the like of the Don Palmer training days. Just don't consider being able to drive on track as good practice for the road.