Last day on the Cornish Local Patch (17th December)

The penultimate day before I leave for back home in Herts.  Instead of retrying for the Lesser Scaup I decided to focus my efforts on the local patch.  However, a little exhausted to say the least I rolled out of bed to set myself the challenge of gulling.  This didn't come to much as the gulls sat on Falmouth docks weren't too challenging at all to be honest, only a few adult Herring Gulls and a few Great Black-backed Gulls, nothing else unfortunately, not even some interesting age groups.  A brief sea-watch from Pendennis Point to follow which produced a distant flypast diver species, most probably a Graet Northern.  4 auks also flew past, equally distant and unIDable but a single Guillemot sat on the water at Swanpool was thankfully close enough for safe ID.  A female Black Redstart on Castle Beach was nice to see, as well as being rather confiding whilst wader highlights included 2 Purple Sandpipers at the point and 2 Whimbrel.  Next, I bumped into Greg Wills, looking for the Black-throated Diver and Red-necked Grebe which he had found not to long ago.  A halfhearted search for both of them and we had to draw a blank but Swanpool Beach was a little more interesting.  It was already getting rather late and I only had about half an hour before the sun would have disappeared behind the cliff.  I had just reached the beach when a 3 Chiffchaffs took my attention on the west side of the beach as they clambered through the ivy on the cliff face and the seaweed.  One in particular took my attention.  The first unusual feature I noticed on it were its orange tarsus?!  Having captured my interest, I soon noticed the comparatively large size of its supercilium, extending above the eye which was much more obvious than the two attending nominate race Chiffchaffs.  Some photos below show the bird feeding from very close range amongst the seaweed and nearby ivy covered cliff face.  It performed very well and was rather tame until dog walkers started using the few meters between me and the bird as a walkway and it suddenly became more skulking and eventually disappeared all together.  Apologies for some of the very poor quality photographs, since the bird was feeding at such a close range and was continuously active, I was struggling to say the least to get it in the frame (I was digi-scoping), let alone a sharp photograph.  I'm still convinced it's a Chiffchaff but these two worrying features put me off, any help IDing much appreciated.

 showing the comparatively wide supercilium

despite being very blurry the all important leg colour is still visible.  Admittedly, the tarsus colour is not as obvious as the feet thanks to the blurred photograph but they were obviously pale (like the feet) as I observed it.

 even more blurry but the leg colour is still equally worrying, the orange smudge below its belly represents its foot.

 here, the supercilium looks comparatively small but still extends over the top of the eye