Try applying pot ash, all stone fruits benefit from the odd application. The leaf curling may well just be the dry conditions we have had. I love Green Gages wonder why the super markets don't sell them ?

They had some in Morrison's this week, Pimpernel, but perhaps you haven't got one of those near you.

It could be aphids on your tree, Geary. Have a look inside the curled leaves to see if any greenfly are lurking in there. If it is, give it a spray with insecticide, but try to find one that doesn't kill too many other insects! Annie