Hi there. Sorry for delay in commenting on this yet another awesome 
find of Mr Finch's! From what Brian's written and described, I see 
no reason why it is not a Larus ichthyaetus. With the clearly longer 
wings, larger size, pale grey mantle and back, dusky smudge behind 
the eye and around to the rear of the crown / nape, and the thick 
black tail band, it surely has to be thisone. 
The pink legs are not a problem for a 1st winter bird being 
called "like juvenile or paler, fleshy-brown with greyish-olive 
tinge." As far I can tell, this is a good record. I haven't been 
able to see the photos yet as internet access is not easy for us 
down here on the coast... 
Shall try to have a look at some point. This record will likely be 
forwarded to the Rarities Committee which is about to be got going 
fully again but I don't see why it shouldn't be accepted.

Colin