Put some electricity into TBE and Kitty
Who keeps stealing it all? Surely the Jag would be fine? 
Why would it be any better or worse than anything else? Battery technology hasn't changed since your dad was born...
Because it would be used regularly? I've not had to touch the 3.2's battery for least a year and it's only been driven once a week for past 5 months or so. Not sure why you appear to suffer such bad battery loss 
Generally, the Battlebus isn't used ever. The Jag gets irregular use, and the jury's still out if the battery is knackered, and TBE gets used most. Currently, because TBE is broken, much like its owner, the Battlebus is getting loads of use, TBE and the Jag sit unused. Neither were flat, and both would have started without issue, but we all know its retarded to leave a lead acid battery for long periods whilst reasonably discharged, or for even short periods when heavily discharged.
So they were topped up with nPower's finest

I'm yet to determine if the Jag keeps accessory sockets live, or if it turns them off after a period of time, then turns them back on when unlocking. Fair to say, as I keep forgetting to disconnect the gayPod, that always appears to be fully charged
