any mites on the backside??? .. looks like all the vital fluids were sucked out if them

ken

Yes you're right! There are some tiny white bugs on the backsides of the leaves (pinhead size). They look like tiny white bits of fluff. There's one or two on most of the affected leaves.

A quick google suggests they might be beech woolly aphid? Is there any non-chemical control (I'd rather not use pesticide unless there's no alternative). Thanks very much Ken, I would never have noticed if you had not suggested it!

Since they seem to be on the growing tips how about cutting the hedge? That would remove the infested leaves for the most part I imagine and might deter egg laying. According to the RHS there is no non-chemical control.

Here is a link that might be useful: Beech woolly aphid