Phil,
I guess it is not very complicated to find general spare parts for a SIG 210 in Germany, but in order to get a barrel it is required by German law to have a German permit for this gun or to have a gun dealer licence. It is not possible in Germany to buy a barrel w/o a permit like in the US.
Here you can see a sketch of a SIG 210.
http://www.asamnet.de/~ehrenred/ersatzt/sig210.htm
I learned CDS does not deliver to the US, but at least you can check for the correct German designation of the parts and it will give you an idea how much it costs.