I'm sorry to hear about Dakota's problem.Â
You might want to join the yahoo group "Orthodogs":
http://groups.yahoo.com/group/orthodogs/They talk about hip dysplasia, among other orthopedic problems, and people there are happy to discuss the pros and cons of the various treatment options.
There's also one that deals with conservative management:
http://groups.yahoo.com/group/ConservativeManagement/If hip dysplasia is truly the problem and it is severe, you will probably need surgery at some point, but often a surgery needs to be scheduled some time in advance - conservative management is a good way to help Dakota in the meantime. The people there have lots of good information as far as supplements and various physical therapies.
However, I couldn't help but wonder, are you sure that the hips are the source of the pain? Looking back over your posts, it wasn't clear just how thorough the exam was to determine that hip dysplasia was the problem. Did the vet watch Dakota walk? Palpate both rear legs? Flex all the joints? Do a CBC to check for infection? There are just soooo many things other than hip dysplasia that could be causing rear-end pain. Even tick-bourne diseases can be the culprit here in the States, although that may not be an issue in Scotland.
As Sarnewfie said, sometimes hips on a young, growing dog will look bad when they really are not. One way to rule out problems in a joint or joints is to tap the joint fluid. If there isn't any inflammation, that joint is not causing pain. On the other hand, if there is inflammation, a joint tap doesn't reveal the cause.
Another problem is that poorly taken x-rays can show severe dysplasia in a normal dog:
http://www.leerburg.com/hipart.htmJust something to be aware of.
I hope this helps you.Â
 Feel better soon Dakota!
Sofia