Doug .. have not heard from you for yonks ... !!!!!! so now, i just hope that you have not put the mokka on your core .. !!!!
I disconnect my battery earth ( hardly drive the Zed any way ) and have never had a core go. If the battery earth is disconnecedt you are not going to get any stray current . It would be a major pain in the arse if you drive your Zed every day. But if it sits with the 24/7 with stray current as opposed to 12 hours once a month the odds are a lot more in you favour I'm guessing. Cheers Dave
if it goes again use waterless coolant. Expensive but I'm guessing that would stop any corrosion problems