The OP called to mind that in Desperate Housewives, some of the girls attend a school where their uniform includes skirts in Dress Gordon tartan.
I am trying to research the use of tartan at South African schools, but it seems most of the tartans in use are for girls’ dresses.
One school in Cape Town has a summer tartan (in green and white) and a winter tartan (a more traditional sett with red in it).
And in Johannesburg, Blairgowrie High School has its own tartan, registered in Edinburgh. But whether it is worn in kilt format, I am unable to say.
In Grahamstown, just up the road from Port Elizabeth, St Andrew’s College has a pipe band and dresses the band members and its army cadets in Graham of Montrose tartan. But most of the time the boys wear grey trousers, just like the boys at most other high schools in South Africa.
I believe there are other school pipe bands in this country, but I have no information ready to hand.
Regards,
Mike