All in good fun.
I had forgotten Argentina drove on the left pre-1945 and one of the bus history sites I visit had several photos of busses of what I think is this one's vintage with the stylized "fish" logo on the front of the radiator. So............take a wild chance.
If nothing else, Gerd, I am persistent.
Now..........Hungary and Sweden also drove on the left at that time so I will have a look around there. I don't think it is British or Italian.
Bill