Hi there,
I only know a few places in the Netherlands.
The first one is in Amsterdam.
Harry Jansen - Luthier - Amsterdam
Harry Jansen is a well respected luthier in the Netherlands.
Then there's one in Rotterdam (about an hour drive from Amsterdam)This is were I always go if I need work on my bass. He's got several basses both for sale and for rent.
Rogier Dieges.
Double Bass Workshop DIEGES - Double Bass Workshop Dieges
The last one is Lucas Suringar
Atelier voor contrabas. Lucas Suringar
He has a shop in Almere (about 40 minutes from Amsterdam)
I hope you get time to visit them all and find something you like
Good luck,
Eddie