The cap badge appears to be different on the man with the moustache. Looking at the photo of the man in the middle with basket in front of him on the left, looks very much my grandfather whom i have a photo of him in the RFA in ww1, i've tried to get a closer up look at it but does n't really help, i could email you a copy if you want of the unit. PM me if you want. The apron on the one looks like an old butchers apron. Prossibly an army canteen