Oh dear...having had the gas recharge only last 24 hours, I took it back to the aircon specialist. They put the ultra violet light over the engine to see the dye they had put in with the gas, and it was all over the front right of the engine!!
With a bit more investigation, two pipes have rubbed together over time, and one has now split, causing the gas to leak. (Pipe alone is approx £200)
The big question is, will the "Warranty Holdings" warranty I got from the garage I bought it from, cover the cost, or call it "wear and tear"?
I await a call back from the garage.....