Leaking inlet manifold

I recently tried to fill my water coolent for the radiator, As i was filling her up i noticed a small water fall pouring from behind the carberreta. I located a new machine cut hole that appears to be missing some sort of bung? Can this bung be replaced or do i need a new inlet manifold?? Any help would be much apperciated!

Cheers Andy

sounds liek a core plug, phone the dealer these may still be available. if not local motorfactors will have a range of sizes in stock just a case of figure out what size you need