ICAO Annex 14 5.2.2.5 A heliport identification marking shall be oriented with the cross arm of the H at right angles to the preferred final
approach direction. For a helideck the cross arm shall be on or parallel to the bisector of the obstacle-free sector.
In other words, the approach and departure should be parallel to the long bits of the H.
Shore side I wouldn't bet on it so much as some of the markings could have been installed by the "who knew" brigade as posted here.
Making sure that there are no bits sticking up between you and the pad has served well so far!
That’s pretty scary - 1000s of helideck landings and you’re not aware of what information the deck markings can give you........
I would be careful with slavishly following that one as there are plenty of old decks around that are not marked correctly!