That really is a run of bad luck!
Unless that wrench has worked on a Europa, it's unlikely he's worked on anything like your 365 (since it's a Renault tranny). But then, with the manual, he shouldn't have any trouble working on it.
I think I would take it out and split it open and see what can be seen. Many years ago, I took mine out and opened it up - and successfully put it all back together - so it's not as daunting as you might think. If it's something obvious and non terminal, you might be able to fix it your self. If it's not obvious, you can put it back together enough to give to that wrench. If you need parts, remember Meca Parts and Alpine-America. As I said earlier, I've been led to understand that parts for the 365 are not as unavailable as I thought. As Joji said, 365s are pretty rare. I think they were used in a Renault, in addition to the Europa, but I believe the 5th gear is a Lotus adaptation.