Went back a few days ago.
That shop is still there but seem to have less Swedish knives and more Finnish. They had some nice looking Finnish knives but you had to take part in an auction to get them (photo).
I also had a look at an antique shop in the Gamla stan area and they had a large number of old slipjoints, some good, some rusty, mainly from Scandinavia and Germany. Prices were around 20 Euro for the really rusty ones to several hundred for the nicer ones. I did not buy anything as nothing caught my eye, but it is definitely worth checking that area out if you have a good knowledge of Scandinavian brands.