The large group photo was taken after WW 1, as the medals they are wearing are for that time period. The photo is probably from 1919 to very early twenties considering the ranks of those in the photo. I can't see the cap tally (band around the cap) on the second photo to tell if it has a ships name or just a generic HMS. HMS would mean it was WW 2 era as the ships names were removed as a security measure. But going from the clothing and the uniform I would guess sometime in the thirties before WW 2. The british naval rating uniform really didn't change much so it's hard to pinpoint the interwar years.