Aug 17 (Reuters) - GDI Property Group Ltd GDI.AX :
* Sale of 233 castlereagh st, valuations and leasing update
* Says settlement of the sale is expected to occur on or around 30th September 2015
* Says buyer has paid the third instalment under the option deed of $7.6 million, taking total payments to $15.6 million
* Says buyer of 233 castlereagh street, Sydney, has exercised the call option to purchase the property
* Source text (http://bit.ly/1gPl6NV)