As you are based at least part of the time in Germany, I would suggest that you enquire about servicing issues with Gossen.
My Profisix (Lunapro SBC in the USA) recently died after about 30 years of excellent service. I had a new Digiflash to fall back on, so didn't replace it, but I would have otherwise considered either having it repaired or replacing it.
If you shoot with flash, the flash reading alternative is worth considering (Lunapro F in the USA). You lose some of the extended low light sensitivity though with that meter.
And in case it isn't clear from the posts above, the Profisix and Lunapro F use the 9 volt battery that, at least in North America, can be found everywhere.