If anyone was wondering where it was on the Roomster, it's here:

Just under the Steering column. Pull the panel from the bottom and it should come off quite easily.

I though I would post this because no-one seemed to know where the OBD port actually was on the Roomy. Just got to get a version of Vag Com that works with it now :(

And that is for left-hand driver :D

Thanks guys - Locked and Stickied