Thanks 'Wills'.. did some more searching and recovered the receipt ....which was actually Jan 12 not 13 - so the battery is 2yrs 7months old, no wonder I couldn't find it.
Warranty is 3 yrs so worth following up.
Thing is I'm marooned
...thems the breaks living in the sticks.
RACV dont carry a battery with any more that 560 cca that will fit in the cradle and the Supercharge battery (dealer 27klms away) claimed on their website to suit the KJ is 305mm long which is 50mm too big. Aaaaaaaaarrrrrrrgggggggh sooo frustrating