The freedom for an European AOC holder to operate within any other European country is not as simple as many think. The flights have to be to/from a "community airport", with offshore installations and mobiles not qualifying.
So this means national boundaries still count for offshore support flights i.e. offshore flights are still subject to the rules of "cabotage".
The only way around this is if a national regulator grants permission for these rules to be varied e.g. the Dutch and British regulators have had a long running reciprocity arrangement. The allows for the current plan for the CHC AOCs in the Netherlands and UK to be merged.
What is very interesting with the Dancopter contract is that the Danish regulator has always refused CHC's requests for the UK AOC to be recognised in Denmark, hence the continued existence of CHC Denmark. The CHC Denmark S92s in Aberdeen at the moment are there under a short term "wet lease" basis.
I do hope the UK CAA are insisting that Dancopter establish a UK AOC. Or will they take the typical weak "British" viewpoint and feel like the have to "do the right thing" and follow the Europeans at the expense of UK PLC.