Tom,the obverse with the 5 crosses is very familiar to me,but the reverse isn't,I'm afraid.It is a pity that we haven't got a Portuguese coin expert on board. Aidan.
I know - obverse is very similar to arms of Crusaders Kingdom of Jerusalem... I have to make some photo!
Tom,I have also seen a design similar to the Jerusalem Cross on colonial Brazilian coins,but it has an armilliary sphere in the Brazilian design. Aidan.