Just had a look online. Looks to me like no one sells them separately from the headlight. All that I can suggest is to try different dealers, see what they say. Also try online places like Fordparts, they may be able to source some for you?
I took your advice and went to a different Ford dealer. Spoke to the Parts Dept and they knew what I was on about and had the part in stock. It did cost me £8.83 though.....
I've uploaded a couple of pics of the part and packaging for the Dipped Beam plastic weathershield/seal.
Thanks Gumpy321 and Ronnie for the replies on the post.
photo (2).JPG 122.19KB 59 downloads photo.JPG 118.45KB 53 downloads