For the para-dropping, the RAF have had a pair of Skyvans and a Dornier 228 on lease for many years from Summit Air of Canada. They are based at Brize Norton and are used by No. 1 Parachute Training School and the Red Devils Parachute Display Team.
The ITT is presumably simply a regular (3-yearly?) renewal, with the option to award it elsewhere if someone other than Summit came up with a better offer.