I quite agree with what has been said about using a dog/dogs to control rats, I used to do it myself back in the days when I had lurchers and terriers. However Harley is a "Non-working/pet dog" and I suspect that SWMBO would have something to say if she found that I was encouraging him to chase and kill rats (You married guys will know what I mean), especially in the close proximity to one of the busiest main roads in Rochdale. On top of that with the "hedge" being so thick and dense it would have been difficult to get a smoker in to the holes where the rats are likely nesting without doing damage to the hedge, which the council and "Joe Public Do Gooders" might not have appreciated.
Anyway there is a "satisfactory outcome" to this situation - The council pest controller has just called and asked me to show him where I thought the problem was. I went out with Harley and showed him the rat runs (Harley wanted to get stuck in and down to business with the rats straight away) and he agreed that there was a potentially quite serious problem building up there and as such has laid bait boxes with Bromadiolone in them - Well out of sight of anyone walking their dogs or children, and he will be back in a fortnight to check and re-bait them.