VAG-COM seems to work ok, I can query controller 17 for instance and it comes up, it's more this VAGTacho that seems to have the problem.

I removed the K-Line (grey w/ white trace) from pin3 in the iso adapter, even though there was nothing on the other side. Interestingly the voltage on that line was less than 1v, but pin 7 in the obd port is 11.5v

No dice with the radio fully unplugged either.

I'll have a look on Vortex, I did a quick search for K-Line but i'll spend a bit more time.

Thanks for all the suggestions