Right bit of an update on this for the benefit of others that may be in this position, I have tried a few avenue to track this part down today;
Early morning email to Euro Car Parts with the Bosch part number and the reply came that they could not source the part.
First call to my local motor factors (A1) , after ringing around they came back with the price of £56 + VAT - they would need to ship it in from Germany and it would take a few days.
Second call was to VEXI in the link above, passed all the details over (Bosch part number etc) - spoke to a guy called Piers who was very helpful. They said they would make enquiries and get back to me
Whilst waiting for the call from VEXI i rang Alfa Romeo - the Alfa part number is 9948397 for the headlight motor (Alfa call it a Governor Regulating Assemby) - they came back with the price of £72 + VAT , also would take a few days to come in.
Got the call back from VEXI, they can source but will need to be ordered from Germany, price delivered to my door is £44. Placed the order and expecting the part middle/end of next week (will be shipped next day from VEXI) Piers did say that they go of the genuine part number given by Bosch - so for anyone else who needs one you can contact them with the Bosch part number to ensure you get the correct part
As 147Dav said above the Bosch part number is 0307853303 & is printed on the back of your current headlight motor.
Hopefully this will cure my problem with my O/S headlight aim :-)