Caddy Heater temperature controls

[Normanty24]

I was hoping someone can give me some guidance regarding the cabin temperature regulator controls on my right hand drive 2007/8 Caddy 1.6 petrol with A/C. Whilst I have had the vehicle for some time I have always assumed the air con was a little weak particularly in this climate in Australia. However I have been unable to control the cabin temperature and it has been blowing constantly hot. Upon investigation after removing the control dials I could see that the mechanical control linkage for the hot and cold regulator was missing, no sign of it behind the dash and can only assume either it was removed and not replaced by a previous owner or perhaps the heat and cooling temperature is controlled electrically. I have checked with the local VW dealer and given them my VIN number they have sent me a quote for a replacement cable linkage but I have no idea where the other end would connect to. Also looking at the back of my heater controls I cannot determine if something else is missing see photo. Having also done some research I see there are some models that have a motorised heat/cool valve so perhaps thats why no cable and if so where the heck would it be. So I have no idea if my heat/cool control is mechanical or electrical or where it would be located. I completely confused and any help would be appreciated.