I have just received a Court Summons, which means I face reaching 12 points for the second time in 2 years. Can I plead exceptional hardship again in order to retain my licence?  Do I now face a 12 month ban or is it still 6 months?

There is nothing to prevent you pleading exceptional hardship again but you are not allowed to use the same reasons twice in any three year period. If you can show new reasons your submission may well be successful. If you fail, it does not follow that the ban should be more than 6 months, it would only reach a minimum of 12 months if you have already received a totting up ban in the previous 3 years.