The diesel 4x4s do hold their value as they were fairly scarce (most people were put off by the VW diesel 'scandal') -- a shame, as the diesel is the better engine in the 4x4 ( I have one!) and much more economical to run that the TwinAir version
But, in spite of their scarcity, and it being the Antarctica special edition (of which, only a few were sold in the UK), being 2013 might put a few people off and the value might affect that. The best thing is to look at ads in Autotrader for similar cars and see what folk are asking. But, they don't necessarily
sell at those prices... I have a 2013 Land Rover Defender, and there are some
very silly prices for these on Autorader. Places like WeBuyAnything will give you a quote (which will be for the trade-in value), but they are notorious for then dropping their offer when they see the car - they will find 'a scratch here and a knocked wheel rim there' and reduce their offer a long way!
There's a few similar age diesel 4x4s on
Autotrader (including a 2014 Antarctica) at around the £4,000-5,000 mark, if that helps at all.