Can't remember if it was you that mentioned battery not good on MG if left standing, my friend has an early ZS, 4 years old, battery gave up at 2 years, he is soon to replace this one, just in case.
Amaron batteries give a 2 year warranty, probably a good buy for rides that batteries pack up around 2 years...
Our weee Celerio has one, a year old, I tested it in the morning after being laid up overnight, showed 12.79 volts........????