I recently moved from the US to Ireland (republic of), I had to do a lot
of research to see how I would get there.  In Ireland they do not have
quaratine facilities that take small animals so I was lucky and was able
to do home quarantine.  Home quarantine still involved a lot of work, you
have to set up a room specifically for them, then an inspector has to
come by and approve it, the you get an import permit.  So it is hard of
you do not have time before your job starts or if you do not have someone
to look after them whilst you are setting up the room, etc.
 
In the UK they do have numerous facilities that accept small animal
quaratine, ferrets, last I checked, still need 6 months of quaratine.
Home quarantine, since they have facilities for small animals, is
extremely difficult in the UK with many many many rules.  There are
several quarantine places of the entire UK so you can hopefully find one
close by.  Remember, however, that there are certain visiting hours and
days.  Since your ferrets are older and probably need more care and
attention that you may be missing out.  6 months can be a long time.
 
In Europe, Germany and Holland, there is no quaratine period, they need
health certificates and a statement that they were born and bread in
captivity (so does Ireland and the UK).  In germany (and I believe
france) if you have more than 3 animals you need a special import
license.
 
The organizations in charge of animal import is usually the department of
food and agriculture.  When I first started looking the web was
invaluable.  Type in "import animals UK" or something along those lines,
and try different search engines.  Good luck, let me know how it goes.
[Posted in FML issue 4289]