Could be the weather but it tends to like an acid soil

Any chance of a photograph? If not, what exactly are the brown patches like? Where are they on the leaf (tip, middle, randomly placed). Are they widespread on the shrub, or only on older leaves? Is there anything visible on the underside of the affected leaves?

thanks for advice-I will look into the condition of the soil and consider the acid aspect.the brown patches are on tip of the leaves and quite random, plenty of new growth looks healthy otherwise I use fish blood and bone for feeding once a year maybe, I am quite busy so don't have time to fuss a lot over it much as I love my garden it takes care of itself.

Browning of the tips strongly suggests exposure to hot sun or extreme wind at some point, or possibly a short period of drought for the plant. I wouldn't worry about it if the plant is otherwise perfectly healthy and you're sure its not gasping for a drink right now.