you can get them from most rocky places or down the sides of some peirs, but.. in the warmer montghs.
the further north you go, the bigger and more numerous they are.
we get a few in hartlepool but only about 1/2lb down the sides of the pier.
i have a friend who fishes from his boat, off the back of longscare rocks [hartlepool] and he gets loads of 4-5lb fish in the summer.