BRCA current battery and motor lists can be found at
http://brca.org/?q=content/homologation-lists/1402 . Battery list is usually update from mid January with new batteries allowed for BRCA santioned events from the 1st April that year. You can of course use them at club level etc providing the club doesn't mind. They can also be used as practice packs at BRCA sanctioned events but not raced with until the 1st April.