Tim Martin gave the blues the lead midway through the first half, before Greg Brabon doubled their advantage four minutes before the break.
COWFOLD - PROGRAMME DOWNLOAD
Jermaine Beer struck twice inside the final 12 minutes to move his side into third spot in the Division Two table, in between Will Lewis pulling one back for the Robins.
Bosham embark on their longest trip of the season to Westfield on September 22 (3pm k.o). Meanwhile Dan Bishop's reserves host Fareham Town at Walton Lane (both 3pm). They fell to a 5-0 defeat at Clanfield in their latest Wyvern East fixture.