A trip to VW and I discovered that they are not available separately, only as part of the full splitter and fitting kit package. I wasn't about to pay £200 for two pieces of plastic so hatched a plan to make my own.
I went to see a couple of plastics engineering companies in my local area but they said they couldn't do it, however a very nice chap at one place gave me a big hunk of acrylic for free
So off I went with the power tools 
Highly specialised work area
Shaped
Fitted
Now, who wants to buy the kit now that its got all the brackets
Jon