From the emails you didn't read:
BATTERIES
NiMh: Efra list 2008 + all previously Efra approved batteries.
For the use of NiMh batteries, please follow the BRCA safety instructions.
LiPo: 7,4 Volt originally hard cased LiPo's (no Maxamps skins e.g.).
When in doubt about the hard case, we will follow the ROAR definition.
Use and charge according to manufacturer’s instructions. Liposack recommended for charging.
Charge regime CC/CV, maximum allowed voltage 8.44 V.
For reliable info on LiPo, please read the ROAR rulebook, pages 33 to 36.