Yellow-legged gull at the horse paddocks

While I was looking through the gulls at the horse paddocks today, I came across this gorgeous summer plumaged large gull at the back. Clearly it's a big bird and it's far too dark to be a British herring gull Larus argentatus argenteus but it's also quite a lot paler than the nearby lesser-black backs.

In the field my immediate reaction was yellow-legged gull, and this seemed to be confirmed when I looked at the photos later and saw that the bird had yellow legs. Notice also that it's quite slender looking bird with long wings.

However this wing pattern had me confused for a while because yellow-legged gull is meant to have a black tip to primary feather p10, but in this case it appears to be completely white, which made me consider first Caspian gull and then yellow legged omissus-type herring gull L.a. argentatus. It doesn't quite fit either of those species though, either in wing pattern or jizz and further research reveals that actually some male yellow-legged gulls can have an all white tip to p10 (Olsen 2018).

Also, on closer inspection p10 does appear to have a black notch near the end and after a discussion on the facebook group Western Palearctic gulls, the general consensus is that this is indeed a yellow-legged gull, and a very smart individual at that.