Victormikecharlie
Hi Nathan
I can also recommend Zephyr Aviation. They have a very nice and fast KingAir 200. They are really excellent AOC operators in addition to the fact that they have 60 + years of flying heritage and their own Long Runway. Close to High Wycombe which although not the closest for you, is 24/7. You want to contact Kate or Andy (ex RAF drive). I'm sure they would be happy to give the very best advise.
Cheers VMC