Some history on the place here http://www.cottoncollege.co.uk/
It closed in 1987. There was security on-site while I was there with what sounded like an Alsatian dog.
Possibly a sports hall on the right
and again on the left
The building on the left,hidden behind the trees, is St Wilfred's Church which is still open - there's another gate through which you can gain access to the churchyard.