Which Warbler?

I've uploaded two different birds for today's blip.  They are different individuals but they might be the same species, or then again they might not!

The small warbler in the mains is either a Chiffchaff or a Willow Warbler. The two are notoriously difficult to tell apart unless you are lucky enough to hear them sing, which I didn't.  

It's a bit late in the season for the Willow Warbler, which is a migratory species, but the colour of the legs and the shape of the head suggest that it is a Willow Warbler, rather than a Chiffchaff.  It is not impossible to see Willow Warblers here still, particularly given the very mild Autumn. On the other hand the shortness of the wings of the bird in the main shot suggest that it might actually be a Chiffchaff rather than a Willow Warbler.

I am reasonably confident that the small warbler in the extra is definitely a Chiffchaff with its dark legs.  

Its an enigma wrapped up conundrum :-)