The results, whilst still not brilliant, are noticeably better. So the learning from this is that it's worth setting up again, later in the year when the light is brighter, and I can have lower ISO and faster shutter and tighter aperture. I caught some images with seven or eight birds together around the various feeders, but only the centre portion was in focus because of the wide aperture.
And the squirrel reappeared, not only taking food, but also doing its best to destroy the feed container!
