Trad Morgans brilliant on track and capable of giving a surprise to many more modern and powerful cars!
Track day organisers are key to a good day. These include GoldTrack and BookaTrack. They limit numbers on track and maintain high driving standards. You need decent tyres for a track day though.
Can recommend track days at:
Castle Combe
Snetterton 300
Silverstone National and International
Ty Croes
Goodwood.
Mallory Park
Best for beginners and a fantastic track Ty Croes. Very little to hit and lots of run off. It's worth putting in racing brake fluid so that you don't boil your brake fluid.
Alternatively can recommend Prescott Hillclimb school, though you don't get as much track time as at a track day.
John