Hi, can anyone advise on the best approach with our copper beech hedge.

It was planted three years ago and has not reached it's full intended
height. During this summer the highest straggly shoots did get to nearly
the intended height.

Question is should we leave the hedge to develop, just cutting anything that
has gone outside the intended shape, or should we cut back again quite
severely (a third of height) to encourage further bushing out?

Thanks,

M.