Without photos, it's just a guess about what might be affecting your hedge. Could it be stress from the recent heat and droughty conditions? Or was your area not much affected?
What sort of laurel is your hedge? If it is Cherry Laurel (
Prunus laurocerasus), it might be a good idea to e-mail photos of your plants to
[email protected] in case it is a fairly recent (to the UK) bacterial infection:
https://planthealthportal.defr...
Good luck,
Virginia