The number of white, brown-eyed, 164cm tall women between 25 and 40 with many fake passports is very small: almost certainly with a state-sponsored intelligence service. Add in the gold crowns, and you've got a pretty good profile of this woman.
You can rule out small countries and countries with bad intelligence services at the time. With her European ancestry you can probably rule out her working for African, South American, or Asian governments. That leaves European and North American governments.
The list then is pretty narrow: America, Canada, USSR/East Germany, West Germany, France, the UK, Italy, Spain. Canada, Spain, Italy, and France almost certainly wouldn't be spying in Norway.
Sweden, Norway, Switzerland, and Denmark are all unlikely, as she seemed "foreign" to the Nordic region. Belgium and the Netherlands don't have much of an intelligence service to speak of, especially during the time, and almost definitely wouldn't be spying in Norway.
That gives the final list of America, USSR/East Germany, West Germany, and the UK.
"English with an accent" (probably) rules out the UK and America. So that leaves us with the USSR/East Germany or West Germany.
Anyone on HN want to solve a murder? My email's in my profile :) I feel like that'd be a really interesting group, even if none of us could put much time into it.