No much else you can do. Then cut them fairly hard back in the spring.

Then feed them some rose or tomato food.

I don't cut my Annabel back as I thought they formed flower buds on this years growth. when it gets too large I remove 1/3 of the stems over a 3 yr cycle .

You can indeed cut them right back Seaburngirl. I normally only cut mine about two thirds of the way in an effort to get the stems to thicken up as the flowers are so heavy they tend to flop but I have cut right to the base and it still flowered prolifically.. They flower on the current years growth.