Thanks for the reply
.
I have checked the plenum drains and also removed the grommets to cut the duck bill ends off and we're then sealed back in place only 3 weeks ago so are still clear too.
I have had the lining and windscreen pillar trims off as well as half of the dash to follow those rubber tubes you speak of and are all sealed completely.
Once the epoxy I used to seal the tubing to the sunroof drain and the connecting piece in the arch had dried and cured fully, with the trims still off I ran a hose over the car and it remained dry. So where this has come from has really got me beaten.
Thanks
Rob