I heard this last week and found it wonderfully exciting! Four Norwegian beaver families, 17 beavers in all, are now in Britain -albeit in quarantine awaiting reintroduction to Knapdale, Mid-Argyll Scotland next spring.
Here is the story
Scottish Wildlife Trust | Beaver Reintroduction
It is doubtful there will be an immediate success going by what happened in the Netherlands, but at least the Scottish project will be able to learn from them.
Beavers in The Netherlands became extinct in 1826 but the Eurasion Beaver was reintroduced in 1988. Numbers have steadily increased after high mortalities, but are still less than the amount which were released. Things look on the up and they have now spread out from the areas they were reintroduced.
The Dutch story http://www.mnp.nl/mnc/i-en-1061.html