Iberian Chiffchaff

In south-east Spain we have Chiffchaffs, the marshes along the coast are full of them in winter, as is our garden, some way inland. In summer they disappear to the north. Several sub-species, largely impossible to differentiate unless its Spring and they sing. Now they have been elevated to full species. Lines have been drawn and redrawn. Other parts of Spain and Portugal have them all the time, Some go north in the summer while others don't and these are said to be Iberian. This one is near the SW tip of Portugal so most likely Iberian, but late September could see migrant Commons, but this far west? Yes according to some, no according to others.