Trung there is only 2 people I have used Don Palmer who focuses on Creative Car control, at Brunters, oversteer, understeer, heel and toe, balancing the car on brakes and throttle etc not strictly track biased but you can translate it to track work, he is expensive £450.00, but I promise you he will teach you to drive faster and safer, money better spent than on an Induction kit for 2-5bhp.
The main person who has given me training is a guy called Andy Walsh (1st Lotus Training), he offers 2 or 4 person days (£120 or £240), goes through similar stuff, but not as intensive, very relaxed, and sets up a small track in the pm to put your new skills into use. This is based at North weald. Andy is an ex - F1 Benetton test driver BTW.
Ricardo, Ronald, and Henry (all off Honda-R) are booking one soon hopefully.
Don advertises in Evo, and do a search for Andy's website.