Drove to pick up takeaway, got back in car every was dead. Breakdown called out. Eventually jump started car, alternator charging ok. Dead battery diagnosed. That does make sense, but want I can't get my head around is when I got home I tried to jump start it with my van battery which I know is fine and couldn't even get a light up on the dash or lock the doors with the remote. I did see on another thread that mentioned the BSI causing problems with door locking, not sure if their connected. Also if I do need to change the battery whats the procedure for getting the black casing apart that surounds the battery to get access to the earth terminal?