Climatronic Fault

Hi all, 

So I've put this up here before and did not get the answers I was looking for unfortunately so I'm posting again incase anyone else that knows can help.

I have an issue with the climatronic system in my 2015 Fabia MK 3. Anything but recirc does not blow hard when the fan speed is turned up. Instead, it blows gentle with the occasional hard blow of air. The fan seems to be going at the correct speed for the fan speed I set but barely any air comes out. Instead Every few seconds a burst of air will come out and then it'll blow soft again. It works fine on recirc but I don't want to have to use it with the AC all the time to avoid steaming up of the windows. 

Does anyone know? I had my garage look at it but for whatever reason that day it seemed to work fine. It works fine for the first 10 mins or so of the journey then it starts acting up.

Can anyone help or know what this might be? 

TIA

Adam