On Tue, 30 Jul 2013 11:05:05 +0100, Broadback wrote:

Sadly there is a drop of 2 metres on the other side, getting it even is
not too difficult with a hedge trimmer, the problem is it tends to
slope, I hope that makes sense.

So it's the sides you are having trouble with rather than the top?

Variation on the board sliding along the hedge top should work.
Trimmer mounted on front of board with blade at 90 degrees to the
flat side of board cutting edge forward. Push board along top of
hedge making sure the leading (cutting) corner is where you want it
to be and the trailing corner is following the fresh cut edge. A
decent length board, say 5' long, will keep itself straight.

--
Cheers
Dave.