2S has NEVER been permitted at a GT12 national. They have always been 1S 13.5 only. It was only added to the rules for clubs to use as some clubs were already running 2S.
It has been proposed that the 2S rules be moved to an appendix to the main national rules rather than remove them altogether. This seems to be an acceptable compromise for those clubs running 2S that still wish to follow BRCA rules, and also clarifies that nationals are 1S only.
Trev