Some More Photos of the Pale Chiffchaff at Barrow Sewage Works!

Over the weekend myself, Steve James and Colin Green have spent quite a bit of time at Barrow sewage works to try and photo a pale Chiffchaff which show characteristics of Siberian Chiffchaff.
Although this bird has been elusive at times and for some strange reason hasn't yet responded to my recordings of tristis, abietinus or collybita calls, I feel this bird is probably a Siberian Chiffchaff!?!
See what you think with the photos below?...