First thing, my interpretation in this case would be that having "discovered" the fault in the flight on the way offshore, you would then be permitted to make one further flight back to your maintenance base. That complies with the alleviation that you can not make more than one further flight.
Second thing, as mentioned above, you would be wise to consider turning round and going home when you discover the fault, to save any ensuing hassle. Your emergency procedures may point you in this direction anyway.