JAA and OGP
The JAA/EU Ops requirements seem unable to differentiate between an instrument approach and the subsequent visual landing.
Whilst an instrument approach is essentially the same whether day or night, the subsequent visual landing is not. Human factors includes a comprehensive section on day and night vision, seemingly overlooked by JAA/EU Ops.
Fortunately, the OGP guidelines take a more pragmatic view and require 3 night take offs and landings every 90 days and these are required to be undertaken at an offshore installation if offshore operations are conducted.
Bear in mind that the Regulatory requirements are the lowest acceptable standard, Operators may opt for more rigorous standards and other Organisations and Clients may demand them.
It always provides discussion at audit time.