I can not see the Scottish Amblance service replacing the King Air's with AW 139.
The King Airs have a pressurised cabin and can fly higher altidues and get from A-B quicker than an AW139.
I could maybe see the AW169 replace the EC135 but not with a AW139 as the operating cost would be very expensive and the AW139 being a larger a/c landing in remote sites would be extremly difficult