Thanks for the suggestions. A solution is proving elusive.
With SONAR 8.5LE Dimension Pro doesn't show as an option under 'Insert Synths' - Dimension LE does though. I've reinstalled SONAR 8.5LE, UA-25EX Driver and Dimension Pro but still nothing.
I can access plenty of sounds via the Cakewalk Sound Centre (this appeared to be part of the download / upgrade although it wasn't mentioned beforehand) but don't seem to be able to alter Pitch Bender parameters (the reason for me choosing to upgrade in the first place) or fiddle with the sounds either. I CAN get a result when Dimension Pro is launched on its' own but still get no recognition on SONAR LE.