2015 RHD D4D with heater issues

[Patrick G]

My mum is having issues with here window defroster , which in this case is where the cars cabin heater blows hot/cold air up windscreen to remove condensation. Upon inspection climate control air diversion valves don’t seem to be doing anything although button and screen register input. I was told to pull hvac relay and wait 5 min, where is this located on my model. 
if this Dosent work what goes into visually checking valve/ flap assembly