My understanding is that if a country does not have its own DS service, people in that country can buy direct from German DS. I assume this covers spares as well as DS sets.
My experience is that, that is not correct.
When I wanted to buy from the german ds or usa ds they asked me to have a billing AND a shipping address in Germany or the states, which of course I don't have.
And then when I contected someone from Geobra (not through DS) and they finally agreed to send me up to 20 parts/sets I had to pay ONLY by bank transfer, for which the bank fee was more expensive than what I was buying so I didn't do it.
This is one of the things the PCC should work for, the possibility to buy form any country and pay with credit card or paypal.