Is there any way to check if there is any gas in the air con system or how to check any of the components like the compressor. I have a 55 plate petrol (bought it last December) and have sorted all the minor niggles and replaced the HG and very happy with it except the air con does not seem to work.

There's a pressure switch in the receiver drier, you should be able to multimeter this out to figure out whether there's gas in the system.

Or just buy one of the cheap pressure gauges from halfrauds that connects onto the system.

I refilled my system with one of their stop leak gas packs, worked a charm. The freelander seems to naturally lose gas charge over time.

one way of telling if there is any gas in is to watch the pump through the side protector while some one switches it on with the engine running, if the middle section does not start to spin then it is more than likely out of gas and when it is gassed up you need to run it at least 10 mins every week or the gas does deplete . hope this helps