Good forward planning by Jet2 to lease in the Titan 757, a lot of airlines do not bother when an aircraft goes tech, or is delayed elsewhere.
Of course this will be a one-off, usually lasts a couple of days max. Nobody could ever match the delays of 2 years ago with Excel and the 767 on the Orlando/Dominican/Orlando...
We all could list numerous routes to start form EGNT, I am sure the charter end of the operation could be a little more imaginative. The Canary Islands are a 12 month operation which everybody will always operate. I am sure there is a market across "The Pond"