If you can get a large image of the photo it may be possible to make out a cap badge or the shoulder patch on the guy's arm on the left handside of the photo.
It is quite possible that he served with a number of units, but it could relate to 153 Heavy AA Regiment RA(TA) but they never left the UK and wouldnt have been in Africa. The 153 could be a battery number and not the regiment number
http://www.ra39-45.pwp.blueyonder.co.uk/haa/page115.htmlThe photo looks later than 42 as it looks as if some men are wearing a medal Ribbon.
Have done a bit more digging. It could be 153 Battery, 51 HAA Regiment RA (4 AA Brigade) who where in NA in 1941.
You might want to try posting on
www.ww2talk.com as there are some Arty experts and also a Veteran of the 78th Div