Hi,
the closest shop to you in Dortmund who also designs latex outfits is
Marquis in Solingen. They help you getting in contact with latex fashion and also explain how to handle. Furthermore, they have many beautiful latex outfits. If I'm right the shop is only twice a week open. So if you plan to visit Marquis just call before or look at their website when they it's opened.
and say hi from me
For just checking out how latex is feeling you can also go to a local sex store. There is often also a smaller are area with latex but the latex quality is very bad. However, you girlfriend can get a feeling for latex there. But please don't buy something there! You will not be happy because of the quality.
Otherwise there is also a gothic shop called
Scarface (Brueckstr./Helle, 44135 Dortmund). Sometimes they also have some latex stockings or latex gloves in the shop.
But for a better choice and quality I would recommend you still Marquis! The shop is something like the paradise for a latex lover ;)
SWAY