The A-10s did indeed withdraw from the UK many years ago. In it's heyday the 81stTFW/FW had six squadrons of the beast co-located at Bentwaters and Woodbridge (with four forward operating locations in Germany).
Today one unit remains, namely the 81stFS at Spangdahlem. The runway there is currently being relaid so the 81st will operate from Lakenheath for a few weeks. No doubt the East Coast ranges are in for a bit of a pasting.