Earlier this afternoon a pair of Chiffchaff were moving through the vegetation fringing Pwll y waun lake, but on closer inspection both looked generally pale grey brown above with largely white underparts, no real olive hues at all. I managed to get good views for several minutes and managed to get a pic whilst one stopped to preen in the winter sun. Didn’t hear them call but the plumage definitely suggests Siberian Chiffchaff although the pic, with the sunshine, generally makes the plumage appear warmer than with the naked eye at the time.