I'm having trouble deciding what this is - I think its Griselinia littoralis, perhaps you could google for pictures to confirm. If it is, this shrub is only moderately hardy, so yours is looking quite good after a winter such as the last one. Any damage currently present is likely to be a result of the cold weather. Cut it back and give it a feed to aid its recovery.

Thanks for the info, if I cut it back it would need cutting back to the ground at some points because in some areas the damage is extensive and very bare. Some of the branches are discoloured and look as if they are dead.

Ah, so your photo No. 1 must show the healthiest parts. It's a problem - many people have lost whole hedges of Griselinia this year and in some ways, that's easier - at least you know you've got to take it all out and start over.