I can see nothing on that link states that you can't collect a car ordered outside of Germany or Austria.
As said previously, the dealer has informed me that I can fill in a form and they will provide the necessary documentation for me to collect the car. (They do this on a regular basis)
An update since then, the car will be insured by chassis number with a temporary license plate (Dealers trade plate) (I've done this before with American imports thinking about it), import taxes will be pre-paid, cross referenced to the chassis no. once the car arrives and it will be taken to DVLA and the correct plate issued.