I dont know the latest i think the local "whichever country" stamping the marriage cert was if the cert was not in English or French (for the french embassy)
The wife went in problem a few years back as you can see on here (it is hi andy paul in disguise) and we didn't go to the embassy to get anything stamped.
In the italian embassy they made some fuss in the end they didn't worry and let her off, although another applicant and their partner had a stand up row about it. I belive the fee was about 30 quid (of course it may have changed)