We don't know of anyone who stocks it in Europe. Kaaz ship it over with the diffs, but they have a policy of not sending out the oil separately because it's heavy and flammable, so it's expensive to ship and you can buy oil of the same spec from other suppliers without paying for it to travel all over the world first.
We use the Silkolene BOA 90LS oil we have in the shop for all our diffs