Graig, persueing hyacinth vases made by Willy Johansson I got a bit of information when I googled Hadeland Willy Johanson. A lot was in English, I don't speak Norwegian either.
Of course trying to find it all back for you didn't work so I better start quoting:
The designer Willy Johansson was born on May 2nd 1921 at Jevnaker, Norway and died at Jevnaker Nov.6th 1993.
1936 Engaged by Hadeland Glassverk, in the glassmaking workshop.
1939-42 The State School of Applied Arts and Crafts, Oslo
1942-45 Engaged by Hadeland Glassverk in the sandblowing section under supervision of sculptor Staale Kyllingstad.
1945-47 Temporarily employed in the engraving workshop at A/S Christiania Glasmagasin while attending nightschool at the State School of Applied Arts and Crafts, Oslo.
1947-88 Full time designer at Hadeland Glassverk
Do you need additional information, please contact me. Torun Sørli
I never went any further then this but may be somehow you can get in contact with this Torun Sørli.
Hope it was any help,