Help identifying a bird from a description

Hi there,

Yesterday evening at about 9.30pm I went into my small bedroom to see a quite large bird perched on the top of the open sash window (i.e. half in the house and half out).  It was obviously attempting to get to sleep because it had its head tucked into its feathers and down.  It stayed there all night, despite me having to sleep in the room and finally flew off at 6.30am this morning.  At one point at about 4.30am I had to go right next to it to look out the window but it didn’t even flinch.  I didn’t get a picture of it because it soon got dark (and I didn’t want to disturb it by putting the light on) but I am hoping somebody may be able to identify it from a description:

Location: Eton, Windsor

Body: About the same size as a large pigeon but I suspect some of that is because it had a substantial covering in feathers and down.  Body colour was cream, with a smattering of scruffy blue down on its chest and pink underneath.  The colours were not that distinct because they had a lot of white down mixed in with them.  The tail was an orange brown.

Head: Small in comparison with its body, brown in colour, with a thin long straight beak about an inch long.  It was quite capable of almost completely hiding its head in its body feathers and down, so I think much of the size of the bird might be a lot of feathers.

Wings: Again, very thick with feathers, cream in colour, with orange brown at the tips.  When furled they were over an inch thick.

Feet: I think orange and short but substantial.  The shortness may be exaggerated by the feathers and down in that area.

It was a very pretty bird and its possible that it had escaped from somebody keeping in a cage.  It certainly wasn’t frightened by humans at all.  I cannot stress enough how many feathers and how much down it had.

Any idea what it might be?  I got quite attached to it in the 9 hours it was perched on my window, although there is a bit of a clean up to be done this morning!

Thanks.

Nic