18 December 2013 - Who is who?

Winter Moth (Operophtera brumata)
Last week it seemed all was done for this year.  Then this tiny moth was seen in the porch - no attempt to hide itself away - motionless.  It was much smaller than the Winter Moths already seen in the garden, outside the window and in the woods down the road.  Consulting UK Moths and Essex moths mentions of the Northern Winter Moth (Operophtera brumata) as well as the Winter Moth (Operophtera fagata) were found.  The Northern is recorded as being larger and doesn't fly as late in the year as the plain Winter.  The only conclusion I can come to is that both species have been seen, but I am still a little confused as to who is who.  This delicate little creature must be the Winter Moth and the ones mating in the woods might be the same - but the one at the window (nearly a third again the size of the others) must have been a Northern Winter Moth.  Does this sound plausible?
The advantage of this photograph is that the moth positioned itself just beneath the fruit of the Cuckoo Pint - or Lords and Ladies - or Jack in the Pulpit - and the image takes on a Christmas feel.  Pulpits, Lords and Cuckoos are very Tristram Shandy which is appropriate as on this day (18 December) Tristram Shandy was first published in York in 1759.  A fitting conclusion to this very confusing post.