The Welsh Dragon
The origin of the Team being from a British military base, it is easy to assume that the first players must have been from Welsh origin and that they gave their team the symbol of their national flag: the Welsh Dragon.
Red and Black
These two colours are the Düsseldorf Dragons Rugby Club. We may assume that choosing gold as a colour for the Welsh Dragon in combination with the Red and Black colours may have been a deliberate choice to represent the three colours of the German flag. But this is yet to be verified :-).