Andy,
Please try this link which may also help:-
http://www.stormbirds.com/eagles/res.../gradnetz.html
This is part of Andreas Brekken's "Eagles over Norway" site hosted on Stormbirds.
I do remember another page, again one of Andreas', that you could enter the planquadrat reference and the dite would hand you off to a map - I, regretably, no longer have that very useful link.