I thinks you will find that this is age related i have one that is 16 yrs old & every so often that happens to mine, i wait till the leaves have died then i cut out the offending branch, (sort of like a snake shedding its skin) to make room for new growth

Not Bay Sucker is it? This usually presents as the leaf edge on one or both sides sort of rolled over, thickening and going a pale yellowy green colour, often with webbing present. Once the nymphs hatch, you can see them on the backs of the leaves, look like little insects surrounded by white fluffy stuff.

Thanks for your input. I had a feeling that age might be part of the problem. However, as the affected leaves are spread throughout the head of the standard, I would make it almost bald if I cut away branches. I have hand-picked most of the affected leaves (took ages) but I'm afraid it will spread to my other ornamental bays.

Thanks, Bamboo. The description which you give is exactly right but there is no trace of any white fluffy staff and close examination of the leaves do not show any signs of infestation such as bay sucker or mites.
Glad to know that you recognise the signs! Thanks, again

The nymphs may not have hatched yet then, or hatched and departed. Treatment is to pick off affected leaves if they're not too many, spray if its all over the place.