Thanks for the swift response. To answer your questions:
1. We bought the property in November 1994 and moved in that month.
2. We moved out in April 2000 to another property that we bought. We moved back to the first property in May 2005.
3. In Sept 2011 we moved back to the second property until February 2012 but did not rent the first property out. We moved back to the first property in February 2012.
4. We bought the second property in April 2000.
Thanks for the comprehensive answer. One final question for clarification - both properties have been held in joint names throughout this period - me and my wife.
Is the gain and relief split 50/50 in this case.