A bit more comment. Their service dress tunics are all of the utility pattern, so probably they joined up during WW1 and not before. 'Thumb in belt' is a lance corporal. Others are privates. No medal ribbons, wound stripes, overseas service stripes or visible trade badges. One, at least, has breeches and the goggles may mean they are motor cyclists, but despatch riders usually wore a blue and white armband.