Black backed gull juvenile (I think!)

A busy morning doing my "big shop" and returning some trousers to M&S then I had to wait in for a parcel which was 75th on the delivery van! 
It arrived just before 3pm, so I was able to rush out and catch the last of the light at Spike Island. Of course there were not many little birds around as they'll all be settling down for the evening, but there were plenty of Canada Geese, black headed gulls and a few coots on the canal. I also saw a few of the much larger black backed gulls and two juvenile gulls hopping around the lock. I am assuming that they are black backed gulls, but they could equally be some other type of gull - to me they are all very similar. 

Maybe tomorrow will be a bit more fruitful in terms of adding to my total. Only 4 to go now....but I am running out of time :)