Brands very rarely does full GP for track day, i think they have 2 this year, and usually its for the bikers only.
Indy circuit is good. Phone em up and get booked in on a novice day. get an instructor with you. A proper track day will be better as its more of an exeprience as you get to see the over fast cars too. Brands is good starter as its nice and simple and has one of the best pit areas