The "medal" on his lapel looks very like the cap badge of the 6th (City of London Rifles) Bn. London Regiment, so a souvenir of his service rather than a medal.Adrian
The centre could have been removed and that is a pin we can see - http://www.fovantbadges.com/bad_sa.htmKen
It looks to me similar to the emblem which St Johns Ambulance Brigade use as their badge.