Doc, re your Redpolls,
As mentioned by northerloon
http://uk400clubrarebirdalert.blogspot.com/ is a good source of information on this id problem. It is quite detailed but without much experience in the field, its accually not that helpful. It is easy to overcomplicate things in these situations. I really struggle with individual birds, but when there is a large flock, its MUCH easier to pick out RARE ones! Try and keep it as simple as possible. Sorry if any of he following is patronising.
Most if not all will be Lesser Redpoll - the smallest, brownest, most streaked ones
Mealy (Common) Redpoll - when seen feeding with Lesser Redpoll are significantly bigger, especially around the head giving a fat neck profile, heavily streaked upper, pale (creamy) lower
Arctic Redpoll - must be VERY grey and pale, no brownish plumage, extensive white patch on lower back (pretty rare here)
Hornemans Redpoll - would seem VERY large if feeding with Lessers (extremely rare here)
The bird in your pic imho seems to be a first year Lesser Redpoll, buffish neck and paler, less streaked underparts characteristic, it does show some plumage characteristrics of Horneman's but without any others in shot to compare the size or a shot of the upperparts, dont get excited!
Paul
