Steve Watt lists him as interred in Wyatt Road Military Cemetery Durban.
His name is also on the memorial wall at All Saints Church Ladysmith
The metal markers are no longer there. Perhaps one of the members in Durban can get you a better photo
See this link for name list, can't load as it is not a jpeg
5602 private John Rothwell was with the 2nd Kings Royal Rifles and died of wounds in Durban harbour aboard SS Simla ref. Durban death register. He is buried in the military cemetery in Wyatt road at the Old Fort where most graves have been levelled; John's included. His name appears on the following memorials; All Saints in Ladysmith/Vaalkranz/Durban Wyatt road/Bury Grammar School.
The War Office casualty list in the Times for 4/5/1900 his regiment as 2nd Lancaster.