So a bit of an update here and something I forgot to mention : -
My vehicle has had a replacement engine, from TPS in 2018 with a load of ancillaries. The receipt for the engine swap stated it was a "later engine". I had rung up the company that both sourced and fitted the engine for confirmation
After taking a look on elsawin, I was able to determine that on the S5 8T, in 2009 Audi had changed the intake manifold from a magnesium to a plastic style intake/plenum. So what I ended up doing is picking a reg from a later S5 that had a picture of the later engine manifold. I then popped that into partslink 24 and take a look at the exploded view.
The part numbers I was getting was 079133340C & 079133110AS. I put a selection of these into ebay and I found the intake manifolds for sale that included the vaccum operated drive unit.
I got that excited I purchased 2 intake manifold units just in case, both of them contain the actuator rod that I need and both hold vaccum.
I have simply removed both the actuators and kept the intake manifolds themselves (with fuel rail) as spare.
Hopefully this post will help someone track down what part numbers to look at.
If you look at no 3. on the diagram with the plastic manifold, you will see how I came to this conclusion.