2011 RR tdv8 interior blower issue

Hi all, I have a 2011 RR tdv8 and after approx 1 hour of driving it seems something behind the dash changes and I loose any air being blown through the vents even if the blower is turned to maximum nothing comes out of the vents but you can hear the blower working ?

Any ideas before I take it to a Range Rover garage I dont really trust?

I’m in Cheshire

Thanks in advance

have you tried selecting the vents manually?

Yep makes no odds pressed and tried every different selection

Well I was going to suggest final stage resister but if you can hear the fan working maybe not that .