Mine has Nav and TV (not digital) and as fas as I can tell, 8 spkrs. Front dash mids, mid woofers in each door and tweeters inside of the door mirror mounts, no sub. It may use an amp in the back, I've never really got to the bottom of exactly how the UK cars were configured in this regard.

Why do the spkr wires need to go to the battery tray if there's Navigation?