Not all aircraft auto transfer on failure of AC bus 1.
You press this button iaw with the ECAM checklist on older aircraft.
I did once (in the sim) have a simultaneous AC Bus 1 fault and SD failure.
No ECAM was shown, but if you looked on the overhead panel, the only amber fault light was on the ALTN FEED pb.
This was apparently to make the point that you can dispatch with an SD inop.
Fortunately all our aircraft, currently, have auto transfer.
Cheers.