Tam bemoans gummint fingers in the vintage photo battery pie.
A couple of years ago, discovering pretty much the same thing, I bought some Wein cells (PX625 and PX13 replacements, 1.35V) from an online camera/video supplier. I struck out in the battery lottery, too — my Olympus OM-1n, Gossen Luna Pro, and YashicaMat 124G all required a mercury cell battery that the gummint won’t let you buy anymore.
I got them from here: Adorama Camera. The one I installed in the OM-1n is still kickin’, although I have to admit I haven’t used that camera much at all since then. And all it does is power the meter, anyway. (This ain’t no OM-2n, ya know. I had one of those, too, but I got rid of it years ago.)