Thanks for the reply AngelBunny.
Since posting up this thread I've been doing some searching and came across national, and regional Rottweiler clubs so I'll be contacting them to see what they can suggest. In time I'll also be talking with our vet and the Rescue to see if they have any other recommendations.
When I'm back in work (out at the moment with injured back) I know of one colleague in particular who takes his dogs about 1.5hours from home for training. His are also working dogs, German Shepherd, so he might be able to give me some information too.
I'm optimistic anyway.