Cutting back a beech hedge

Well now is the right time to be pruning Beech plants I'd say. They usually respond well to pruning too so it shouldn't be a problem.

Might want to wait for a few other opinions before you butcher them though!

Cut it back in stages now up to 4 ft. off the face side.
Trim the top in September, cut the other side this time next year.

We have a long beech hedge too. My neighbour has advised us to cut back in June & October, but now would also be good I think, and maybe not too drastic all in one go, as your gut feeling already tells you - one golden rule is to avoid pruning hedges during birds' nesting season, so if you do the first haircut straight away you'll be safe on that count.
Bob's strategy sounds good.

I cut one back with a 5inch trunk leaving no branches intending to use it as a post. To my surprise it has made a full set of branches and doubled its height in about three years. Now should be good time to prune it.

we reduced the ex neighbours boundary hedge to our garden, from 60ft down to 16 ft in february 4 years ago. new neigbours delighted. trunk width 8in or more. since then it has thickend up and we give it a trim every october . once all the leaves have finally gone we do a final tidy up in feb. we had all hoped they would die as they really shade both our gardens but they are happy and healthy and as there is less shade the rest of the garden is happier.

You can find chapter and verse on what to do with your beech hedge at http://store.ashridgetrees.co.uk/Beech-Hedge-Renovation

Good Luck