Just now, PetrolDave said:

Very unlikely, the passenger and driver side heating comes from one common heater matrix.

 

Far more likely is a problem with the temperature flaps in the HVAC system, you really need to get a scan done with a diagnostic tool such as OBDeleven or VCDS to get the details.

I thought that because the coolant is not boiling and it’s a good colour.

1 minute ago, lockstock27 said:

If it's climate control there is a reset for the electronic vents I think which could be worth trying. I have the older manual controls so I can't help you there I'm afraid.

 

I reckon it will be your heater matrix. I had the same. Silicon bag in the expansion tank had burst and contaminated the coolant. Flushed the coolant system, changed the expansion tank and replaced the heater matrix and it's all good now 

Ye I have sent it into a garage today so hopefully they run a diagnostic on it. Because I don’t have one myself 

Same issue on mine. I tried a few flushes but it didn't work so I had the matrix replaced last week and it's nice and toasty now.

 

Skoda wanted over £2k. I paid an Indy £370.