Posted: 12/04/2015 at 07:37
As well as using the Fungus Fighter I'd clear any rubbish from the bottom of the hedge and give it a feed with Fish, Blood and Bone according to the directions on the pack. Strong-growing plants succumb less readily to fungal and other attacks.
As for reducing it's height, go ahead, and cut the sides back too - you'll be surprised and how quickly it regrows. Just check that you've no birds nesting in it first - it's a bit late in the season to cut hedges.