I’ve just bought another defender 90, it’s a 1998 300 tdi CSW, the guy who I got it from was in his late 70s, not that it matters we all make mistakes. Apparently he fitted a battery the wrong way round ie positive to negative and so on, and it was only on a second apparently. The problem now is the battery is discharging over 24/36 hours, I thought it might be the battery so I fitted a 100 amp battery from my other landy and yep it’s discharging as well. I hate electrics and have next to no idea. Any advice/ suggestions will be appreciated.