@MartinSim,

This was a quote from Cam Tech Craig within the below link in a thread that touched upon batteries earlier this year. Opinions might vary although Craig seemed to rate the 4.4 battery:
"... my 4.4 is simply phenomenal on battery life! I have recently left her for 4 or 5 days constantly opening the doors in the workshop (doing some interior mods) & she still had no battery issues...Must be at least twice as long (before it goes flat) as my last FF & thats got a new JLR battery (and imho is one of the better ones!)...

My point is... to say, I thought JLR sorted the battery life issues out on these later cars, what with glass mat batteries etc etc... AGM batteries have a 3yr warranty by JLR "

http://www.fullfatrr.com/forum/topic29401.html

:thumbs: