So, my freelander is a MY08 and has never had an aircon Regas in my ownership of five years and 90,000+ miles. It had recently developed an aircon rattle so hoping the Regas solution may clear it...

Today it went into ATS as I had a discount voucher for a Regas and bacteria clean. After the service I asked, did it need much? The response was, gas was low and it had no oil. Receipt shows 10g of oil was added, I didn't have time to ask what kind of oil and where it goes but I assume it isn't the usual 5 30w stuff

The rattle has gone for now, I will update the post if and when it comes back.

Typical response when they have to give one....

No, it's not 5W30, it's a special aircon (polyalkylene glycol) oil.
An aircon system like FL2's has inside about 200+ grams of oil.
It is distributed between various system's components, but the main component that holds the biggest quantity of oil is the compressor.
They can't extract it just by vacuuming the installation.
They can only extract a small quantity that's on the pipes or components near connecting ports.

Well, I can honestly say if I had been told before today there was oil in the aircon I would have thought they were pulling my leg.