British WW1 Brothers Photo Group. Twins??

Nice selection of photos showing two brothers who served during WW1. There are a few interesting detailed photos including one brother with early rifle and full Pat 1914 marching rig and the other brother in the medical corps uniform. Im going to take a guess that these two are twins, found amongst the lot was a 1916 dated photo card with sentiment showing two French soldier twins! There is no evidence of where the two lads where from as this group was found recently in a Cardiff skip but one St.John's rugby sports photograph is marked ''York'' and there is another card showing a street in Manchester.