Speaking as a gatwick radar controller, I've never heard of anyone being asked for 180kts to 4.
I'd say over 30% of aircraft inbound to gatwick reduce speed below 160kts outside 4dme. The worst offenders in my experience are BA 735s, A330s and Easyjet A319s. I wonder if there's been a change in Easyjet SOPs or an increase in training as Easyjet used to be a lot better?
I'd be happy to let every aircraft reduce below 160kts at 7dme but the increased spacing requirement would lead to unacceptable delays. (unacceptable to the airlines!)