Sept 22 (Reuters) - Rockwell Diamonds Inc RDIh.V :
* Rockwell provides further update on three subsidiaries in business rescue and provisional liquidation
* Provides further update as to developments with Rockwell Resources RSA , HC van Wyk Diamonds,Saxendrift Mine in South Africa
* Istotron, among other indicated to work with provisional liquidator to buy 3 subsidiaries out of provisional liquidation process