Prob -Yellow -legged Gull

Last night about 7.10,I noticed a group of 14 LBBGull heading west,as I was watching/scoping a kestrel at the time I decided to have a closer look at the gulls immediately one stood out to be a grey backed gull, similar in shape to the LBBGull's,as it banked sideways the yellow legs could be seen.All though I am not 100% on this it is well worth looking at all groups of LBBGulls at this time of year for a Yellow Legged.!!!!Good luck