Make sure you get the right battery - there are threads on here about it. The later stop-start models have a more expensive type of battery, which you don't need. One thing I had to check - the standard battery has a small breather pipe coming out of one end. I found that the new (Exide) battery didn't have one. Instead it has a blanking plug in the hole, which you need to lever out with a sharp tool. Obvious when you know what to do, but I was initially scared of damaging the new battery!

See http://www.freel2.com/forum/topic11221.html?highlight=battery

Does anyone know if disconnecting and reconnecting the battery would clear stored fault codes? MY10 TD4 SE Auto

It won't. You need a suitable diagnostic device for that.

another reason to get the Faultmate FCR... MY10 TD4 SE Auto

Just to add my two-pennyworth:
Took delivery of my 2013 HSE Lux a couple of weeks ago. It is fitted with an Exide 80AH 700 Amp (SAE) battery (vent connected at end). I was having a play with the radio/DVD player (as you do) with the engine stopped and had the 'battery low, system will shut down in 1 minute' show on the display. Didn't expect that on a new car, the day after delivery! Anyhow, connected my CTEK XS 7000 charger, set at 14.7 volts and left it to it. It was clear that it needed quite a lengthy charge but did come up to 95% after 3-4 hours on bulk charge and another hour or two so on absorption. Have not had any problems since. A bit disappointed that this was not part of the PDI.
However, not all batteries with low voltage are necessarily on the way out; I guess it is always worth trying a proper charging cycle first, with a decent charger that controls gassing and doesn't try and make the battery act as a kettle! 2007 SE Manual : Gone and missed but 2013 HSE Lux is better!
Series IIa : Gone but hopefully still alive.

Low battery warning on the radio is normal, it is just there to stop you leaving the radio and draining the battery completely, some manufacturers have the radio automatically turn off after a few minutes, Land Rover chose to have a warning displayed before the radio turns off.  p****d off with a Digital Keyboard Warrior