That was my original plan, but the hedge was now trees and cutting it back
to 6ft high left me with plain trunks between 8" and 16" diameter. The
trees were far too big for the available area. Best to start again, I
feel.
--

I took a dratic approach to my beech hedge at my previous home. What I had
was trunks 18" to 24" diameter which were about 6 feet high and the hedge
was only drowing above this point. I tried bending down the branches but
it was a feeble effort so I cut them all down to ground level with the aim
of replacing them the following year. To my amazement in the spring
thousands of new shoots appeared from ground level. I kept the ones that
were in the hedge line and I within three years I had a really healthy
copper beech hedge of about five feet high and 30 inches wide. If you have
the time it may be worth a try.

Bob