Despite the north and east of the UK sinking under the weight of rares, the best we (that is GRG, not the royal 'we') could muster at Uskmouth was an abietinus Chiffchaff. If you're an international quality squinter, the photo below should enable you to make out a Chiff with pale greyish-green upperparts and what appears to be (as compared to collybita) a greater distance between the tips of P4 and P10 (and indeed between P4 and S1). All terribly interesting and, according to the next edition of Svensson (in prep.), reasonable indicators of abietinus over collybita. Of course had it been a mite greyer, some numpty would have claimed it as a tristis, largely due to the fact that a good proportion of people don't know what tristis looks like. Personally, I feel sorry for messers Dean and Svensson, they write a perfectly good paper and no muppet can be arsed to read it.