I would very much doubt there are enough people wanting to fly direct to South Africa from BHX (SAA couldn't make it work from MAN back in the day) and even if there were they wouldn't be able to go non stop as the runway is too short (at the moment
)
Or is it just BHX is not attractive to long haul airlines as compared to LGW
or LHR
Doesn't look like it......never has been, probably never will be!