how can I install the dutch interface in LO

After downloading LO, the dutch version for the main, languagepack en help files (deb pkgs) and installing them in the proper way, I’m still unable the get the Dutch interface working.
Trying tools>options>language settings give under user-interfaces English as the only option.
My OS is Linux, Ubuntu 14.04 LTS, I am a reasonable experienced Linux terminal commands user, but nevertheless I am stuck!
Installing earlier LO versions were always immediately successful, so either I did something stupid, forgot something, or might there be a bug in one of these dutch-related packages?
If anybody could help me, I would be most grateful.

Sorry guys; I found the answer in the LO helpfile. It was my own stupidity: did not re-install Dutch as my system languages after an ubuntu update. Doing such an re-starting LO, my problem was solved! Hurray!!!