Privet aphid

My privet hedge is looking very sad, a lot of leafs are yellow blotchy with aphids on the undersides. Do I need to spray or will they go when the colder weather arrives?

 

Ii don't think I'd bother spraying now but keep a close eye open as the weather warms up next spring.

 

I've never seen aphids on privet, but the yellow, spotted leaves are common. Privet isn't evergreen, although people tend to think it is, but it will always drop some foliage from time to time. Usually nothing to worry about though.
The healthier the hedge is, the better it will manage to shrug off any potential damage from insects etc, so keeping it properly trimmed, and clearing debris from around the base and adding a mulch now and again will help that.
It can be prone to honey fungus though, but it isn't possible to tell from the photo.