The main problem is not Jack-ups but small NUI's (normally unmanned" installations. These are small.....sometimes monopods with a helideck on top and often many miles from any other platforms. On dark grotty nights there are no other visual clues apart from one circle of lights. Nothing else around.
Occasionally even the most experienced crews have to work hard to keep disorientation at bay during an approach.
I enjoy night flying and spend much of the winter doing it but there are times in certain weathers that I don't look forward to the evening shuttles.