Today I travelled down to Cinerford to visit my in-laws and collect my son when my father-in-law asked me to take a look at his hedging as it has some fungus on it they where his exact words now the hedging he has is a Prunus laurocerasus rotundifolia
Laurel is it’s common name.
Looking at the leaves they show signs of a white to light grey mildew also the leafs are turning in on them self’s I will try and upload a picture of the leaf’s but I think I’m at a upload limit on the web site
My son had a hedge that got this virus that made a fowl smell when you cut it and killed the hedge in the end and we had to dig it all out.
Laurel can be vulnerable to powdery mildew and your grey covering sounds very typical. The leaves will curl in as the tissue dies. Am assuming you didn't find any bugs inside the curled up leaves?
powdery mildew is caused by overcrowding and plants suffering stress eg from being to dry. I suggest that you trim off the affected leaves to improve the appearance but don't prune to aggressively if is is rife as this will stress the plants more. Give thenm a good watering and mulch. You can get spray treatments for powdery mildew although not sure how effective these are once it's got a hold. The plants should survive and recover anyway anyway it's more unsightly than anything else. But a good feed and spray treatment at the start of spring next year should help prevent it. Also make sure you clean up any dropped leaves and bin these as they will be carrying the fungal spores.
Chrissieb after a search on the net I came to the same answer as you powdery mildew and told the in-laws to go to a garden centre and buy a pestacide to treat their hedges I will also inform them of your extra infromation big thank you