Gents
I used it again today for an hr or so with just the radio on, parked up once I got home, locked it up and 2 hrs later checked the CTEK battery level indicator and it was yellow already! What could be causing such a drain any ideas?

try pulling the fuse for the nav unit overnight and see if that stops the drain.....

Cheers stan, sorry but do u know what fuse number and what box it's in? Am still unpacking from a house move and my user manual is buried somewhere

Pulled the fuse for the satnav/stereo unit overnight, CTEK indicator still showed a drop from green to red overnight, indicating a drop in battery level

Any other ideas?

keep pulling the fuses until you find the culprit.. its a process of elimination..

If you can, disconnect the battery -ve lead when the battery is fully charged and leave it for 24 hours.
Then either check the battery voltage with with a multimeter or reconnect the -ve lead and check with the Ctek.
This will either show a faulty battery or confirm there is indeed a drain on the car.
New batteries can fail.