The dealer price is way OTT, as is Kwik fit etc.
When done properly the existing
R1234yf gas in the system is recovered and you only pay for the additional gas required to return to spec. Oil and dye is added at the same time.
A quick look up shows the current Golf system needs 460g total, couldn't find the Leon but it'll be the same system.
Prices vary but my local specialist charges £29 + £10/100g gas.
So the maximum cost would be £79 for an empty system, more likely to be around £50.
I'll get mine done in the Spring, it'll be 4 1/2 years old and whilst it works just fine the lubricant should prolong compressor life, and they are around £500 to replace.
CACS Derby