Originally Posted by John V6
Either buy or borrow a battery tester. Your local garage will have one. If you are in East Suffolk you can borrow mine

Age isn't necessarily an indicator of health.

More details here

Interesting that the content provider of the oft quoted GoMoG`s much valued Morgan related website, is seemingly not welcomed to post on TM by some here...

I have found that some battery`s have the week/year date code stamped on top of their negative terminal.

As Richard suggests, over the years such has been the "advance" in terms of on board digital electronics, that we may have moved on from the possibility off just disconnecting and reconnecting of a vehicles battery causing the ECU to adopt a limp/get you home mode, whereby more modern vehicles can throw up all sorts of fault codes to scare one to death...!!! Thus while a battery isolation switch might still be a good idea....????