Has anyone had a kind of damp/musty smell through there heater vents before. Noticed the smell for the last week when heat is coming through. Any ideas???? My car is only 9 months old so shouldnt need a new pollen filter or AC re-gas yet.

Did it rain much in your neck of the woods recently (is that a rhetorical question, since you are in the UK )? A LR bulletin regarding "water ingress" in the passenger compartment of the Sport lists this among the possible causes:

Symptom: Water ingress to passenger side foot well, water
dripping from the glove compartment area. Note:
There may be a delay of days between the vehicle
being subjected to water and the complaint of
water ingress arising due to the time taken for the
water to soak through the pollen filter.

Potential Root Cause:
Plenum chamber panel not securely clipped,
allowing water to pass through the air inlet,
positioned on the passenger side of the vehicle,
and collecting in the pollen filter.

Keep in mind that this is a North America TSB, so things may be switched around in LH drive vehicles. Perhaps your pollen filter didn't quite get soaked to the point where water started dripping in the foot well, but it absorbed enough to cause that musty smell through the vents as it dries out... Just a guess, but considering your car is so new I cannot think of another cause. 

Darren wrote:

Has anyone had a kind of damp/musty smell through there heater vents before......

^  James A. Cadet

07 Range Rover Sport S/C
Chawton White

This can happen if you are not using the AC - turn it on for a few minutes (cold air).