Alex Barnes and Luke Gregory had given Bosham at two-goal cushion inside 25 minutes, before two quick-fire efforts from Nkanyiso Mbambo levelled the game ten minutes later.
Coombes joy was soured somewhat in receiving his marching orders before the final whistle, and will be a miss for the side in the coming weeks.
Bosham: Redman, Bulbeck, Hiscock, Blanshard, Spicer, Bishop, Barnes, Coombes, Gregory, Terry, Lidster. Subs: Lewis, Smith, Desi.
Cowfold are the visitors to Walton Lane next on Saturday, September 15 (3pm k.o).
Dan Bishop's young reserve side were defeated 3-0 at home to Petersfield Town in the Wyvern East - they travel to Clanfield on September 15 (3pm k.o).