I admit it, these things really do my head in. I find the 'subtle' differences between Lesser, Mealy, and Coue's Arctic Redpolls very difficult to master. I spent a good while watching a flock of 60 Redpolls at Broom this morning and although there were some clear Lessers in the flock, there were also a lot of intermediate birds too. The birds above are some of those which weren't obvious Lessers (although the top two are perhaps rather debatable...)
(The images are straight from my GX7 via my iPad. I may get around to re-editing them, or I may not)