Ken,
I'd say that was it. Now you've given me something to go on, a bit of browsing for the
Grey Goshawk shows a white 'morph' that is all white with the orange cere.
Glad it wasn't a sulphur crested cockatoo trying a new diet
I must go and buy a book about birds. Given that I'm surrounded by them and that the weather is bad, may as well use the binoculars for other than star gazing.