Have you had a really thorough look for caterpillars?
Some of the holes look rather like vine weevil damage but lots don't. If you have a good nursery locally it might be worth asking them.

I joined this site in 2008 by asking the exact same question when my daughter and every other hedge on her established estate, was stripped by vine weevils. I was recommended to use Provado to get rid of them.

Thank you both so much. I've heard of vine weevils only. I must look it up. Thanks for the help.
Can I ask would such a thing make the leaves go yellow because some of the hedgeing is glorious and more seem to be struggling

My understanding is that vine weevil grubs will eat the roots of many plants, so that might be causing the yellowing.

Will the Provado kill the grubs underground.