Was the mobile van parked up in the lay-by just before you get to the roundabout at the Gyle? It's a favourite spot for them to park up as they're really difficult to spot until it's too late. Of course if they wanted to prevent speeding, as they claim, then they would select a much more visable location.
On a similar note I discovered recently that my cousin was pulled for doing
exactly the same speed, in
exactly the same place, by
exactly the same police officer, but was only given a warning and sent on their way.
Exactly the opposite of my 3 points and £60 fine some 3 weeks earlier.
Perhaps I should get breast implants as that would appear to be the only discernible difference between the two situations!