I think all these images are before my time as when I was a lad the terminus was on the other side of the road with the buses going clockwise round the Green. My cousin lived around the corner from here and we often emptied the used ticket box to to give us tickets to play with.
No.4 ran from Southwick Green to Rottingdean in the 50's. Was a favourite trip when I was a child. Usually caught the no.2 back to Southwick, which came through Woodingdean (and still does), whereas no 4 travelled along cliff top from Brighton.