I believe the Scottish Ambulance Service does private training as well as there own staff. If you try and find a contact number for the training department they may be able to help you. It's the D2 course you want as D1 is for non emergency driving and is only a week long course compared with the 4 weeks for D2 (used to be 3 weeks but is now a 4 week course as off July 2016)
Hi m8, I'm out of my depth on this one but I found the topic interesting so I looked into it for purely selfish reasons I may do it myself, Google came up with this Ambulance Training UK - FTS Solutions - Home I'm not plugging them by any means because I don't know them but their website says they do various locations throught the UK, could be of use to you or not. Let us know who you go with. Now back to my line.
Yes mate I know a lot of people who have paid good money for blue lights courses only to be told there not accepted by most employers - pretty gash really, but from what I'm aware of col's probably found a decent provider. Just make sure it's D2 and make sure it's NHS approved (that's the biggest factor). If it isn't NHS approved I'm pretty sure itll have a massive impact on whether you'll be legally allowed to drive on blue lights in the U.K. Might be worth finding out the qual details then ringing NHS jobs or a local station or something to just double check if it's transferable to the NHS - it's a mega grey area due to how strict UK driving/contractor driving laws are. But food for thought anyway, Hope this helps anyway bud.