There is a list of batteries and amperages etc in the pulldown list. Never looked to see if it had an AGM or Lead acid option.
AFAIK the 'smart' system was on the facelift models ( 09/10) - there was never an auto start stop system but AGM batteries are more resistant to charge 'cycling' according to the workshop manual.
The smart charging is not software but is part of the alternator control and battery monitoring system. There's loads about it in the workshop manual PDF's if you want to read up on it.
I fitted an AGM and reset the battery via the GAP IID tool. I often leave it for long periods and it never fails to start. If I leave the ignition on for a while it will give me a low battery warning and then shut down to stop it draining - it's smart enough for me.
If you had a lead acid battery already of the right capacity then unless you have problems leave it alone but JLR obviously had issues and changed them for AGM 2012 TDV8 Vogue (L322)

ah that makes sense, so the "Smart System" you refer to is nothing more than what was standard spec on MY10 onwards L322 vehicles, basically the in dash informing you that the battery is low so I'm gonna shut down, all standard fare and no dealer intervention or any ECU firmware upgrades required when simply replacing a stock Lead Acid with an AGM - all of this I assume came about when JLR informed Main dealers it was the best thing to do at the time and the easiest option to get customers off their back during their 3 year warranty

NB I also see that some owners have changed the interior bulbs to LED, and that has also helped with the battery drain issues those owners had !

The Smart System is the smart charging system, introduced with the 4.4 TDV8 at the 2011 model year. The press pack had an embargo on it till 17th June 2010. Thought it was in the Wiki…. Not sure….

Ah, here we go….

https://www.fullfatrr.com/gallery/albums/u...elease.pdf 2011 Range Rover Vogue SE 4.4 TDV8

Previous cars :
2003 Range Rover Vogue TD6
1999 Discovery Td5 ES
1995 BMW M5 3.8 6 speed
1992 Range Rover 3.9 Efi Vogue
1992 BMW M5 3.8
1988 BMW 735i SE
1989 Ford Sierra XR4x4 2.9i
1981 Ford Fiesta Supersport

I have 2011 tdv8. it came with a Yuasa YBX5019 100ah 900a battery and I'm always getting the "low battery please start engine" warning. It doesn't seem to be an issue though, it always starts first time.

There was an issue with that message coming up too early, Land Rover changed it with a software update I understand.

Obviously not an issue as such, but think it’s a bit sensitive…..

 2011 Range Rover Vogue SE 4.4 TDV8

Previous cars :
2003 Range Rover Vogue TD6
1999 Discovery Td5 ES
1995 BMW M5 3.8 6 speed
1992 Range Rover 3.9 Efi Vogue
1992 BMW M5 3.8
1988 BMW 735i SE
1989 Ford Sierra XR4x4 2.9i
1981 Ford Fiesta Supersport