Hi there, needing help to identify bird!

[sheiladrums]

Hi, this is my first visit to the forum, and is posted in frustration coz my husband and I have been unable to identify a bird which visited our garden yesterday. Any help would be appreciated.
It was large, maybe 12-14" inches from top to tail. Mostly green on the upper part, but wings and lower part inc. tail (which was long) was darker slate-y blue. Had a black plume/puff on top of its head; particularly noticeable were its red beak (short, powerful, seed-eater?) and red eyes. White patches in front and behind eyes, and across chest; and when it used its wings, they were red underneath! It perched in our apple tree and eventually descended to feed briefly on the fallen apples on the grass underneath. I heard it make 2 or 3 different types of calls, a screech-y sounding one and a more chirruppy descending sound. it was quite stunning and we spent half an hour observing it.
We've had a look through books and reckon it's not a native species, maybe something exotic that's escaped. I want to upload a photo, but don't know how on this site - advice would be very much welcomed!!
In hope of solving our mystery,
regards to all
Sheila