Have just heard about a new strain of powdery mildew which affects Aquilegias.
It is fatal to affected plants, so any plants that show signs should be dug up and burnt.
It was found in about 5 known sites last year, including the national collection, and there is no treatment.
The picture that I saw, looked like powdery mildew on any other plant.
Love cliff richard but please don't tease