15a. Collar five yanked off. (7). ?A?D?K?
5d. Late support for said drink. (4) ?I?R (Is it pier, if so why?)
6d. River trip after state opening. (5) ?T?U? (Is it Stour, as that is the name of a river, trip is a tour, and S comes from the opening of the word 'state').
I hope I am getting better at this as the weeks are going by.