Aircon issues

Hi. I'm new here and drive a 2016 Mkll Skoda Superb 2.0D (CRLB) SE Business Estate which is suffering from an aircon issue.

I bought it and the aircon failed after a week. I found there was a leak from the pipe/condensor junction caused by the inclusion of a steel locating pin in the pipe flange and condenser flange. I repaired this, re-gassed and it was fine for a couple of days. Keeping this short, if the car is parked in the sun and the outside temp is 24° or more, the aircon shuts down. The fan surges between around 75% and full speed while the air temp from the vents goes up. It's OK in the morning when it's cool or after driving around 8 - 10 miles which I presume brings the underbonnet temperature down, and switching the aircon off and on again. Checked it out with a Solus and got: Fault code B10AF04 Air Quality Sensor Defective. The sensor was replaced and all was well for a couple of hours,  until I switched the engine off and left the car in the sun for 30 mins. Previously the fan ran at high speed and the airflow from the vents was uneven. This was all fine after replacing the sensor. 

So, start off in the morning and all is fine. Stop and leave the car in a temperature of 24° or more and the aircon fails. Drive a few miles, switch it off and on again a couple of times and all is well again.

I've been around the trade for close to 50 years and I'm stumped.

Any thoughts please?