You should be able to date your tyres to an exact week of the year, for example the date code should read something like this 4114 which is week 41 of 2014 . The recommended replacement interval for the tyres on an MGF or TF is 6 to 8 years maximum is 10 years provided they are not worn out !!!!
So yours at 2011 or 2012 are very ready for replacement .