ok - here we go, I have the decision (with all details) of the "Schweizerisches Bundesgericht" somewhen in the 50's or 60's at my office. I'll check it on monday. (And if we really want to stay on with this: 70 years ago there were over 50 breweries worldwide with "Löwenbräu" in their name ...).

(I/my family had a similar fight with Martell brandy from France, we being Martel (one l only) wine-merchant's in St. Gallen. It was settled between my grandfather and the french, since then the name "Martel" for our family-company doesn't stand alone anymore, it is "Martel AG St. Gallen").