I've been using an IBS split charging system from TBRUK LTD - Run by Enthusiasts for Enthusiasts
- it was about £135 (special offer on at the moment) and did a great job and gives nice pretty display of the state of the batteries and the charging.
As a 3rd battery (already have 2 in the LC) I have an Oddessy deep cycle battery which has also done a great job, although I heard after buying it that the the supplier has had to return a few - mainly issues with the terminals..
At one point the children had left the headlights on and we hadn't noticed, the IBS system automatically joined the extra battery up and we started fine.
I have also fitted an split charging system from Antalis before (around £90) - this looks very solid (read indistructable) and does the same sort of things although I don't think it will join the batteries for emergency starting and it doesn't have a display - this had to be bought seperately and ISTR we used a Pirannah system.
Split charging systems are great, but at the same time, make sure that your alternator is in good condition (strip it down and check comutator rings and brushes) and also check everything electrical that you will be taking to make sure it uses the least amount of power as possible.
The one things we forgot to take with us was a 12volt charger for my wifes phone, but we did manage to pick up a cheap 1000w invertor (£50) on ebay that resolved the problem, but not the most economical solution.
If you look on ebay you can find some great 12volt supplies for laptops, etc as well as some good 12volt battery chargers - we got one for recharging batteries in torches (LED) cameras, etc.
Look to get LED replacement bulbs for the interior of your car. At TaskLED Home
George does replacement bulbs for the dome lights in an LC, not sure if they will fit in a LR - you will find that you have the doors and boot open a hell of a lot and of course these will be draining your main battery.
Take a small charger for your car battery, a 20-50m extension lead and international travel adaptors - if you end up staying on a campsite for a few days you may want to plug your aux battery in to the mains to keep it topped up - obviously check that you can have the charger on the battery whilst the battery is in use.
Finally thoroughly test your split charging system before you go - run the aux battery flat and make sure that it gets recharged properly and can hold the charge.