212man, personally I've found it an enlightening discussion, and worth the two pages, despite what others apparently think. I was forced to dig out our procedures, and include pertinent parts here.
All our platforms had the circle and H, but I have no idea what standard they might have complied with, if any. One platform had at best 120° arc for T/O, landing, rather than the 210 splay called for in the CAP. Single pilot, with the wind in an unfavourable quarter, it was necessary to come to the hover along side the platform, looking across the cockpit, and slide to the left to get over the landing area. We did go two crew later. Checking just now, I see the authority has published a document which is almost word for word of your CAP.
You can see from the following why I said the operation relied on airmanship. In my 27 years there was never any incident.
HELIDECK PROCEDURES
The Pilot in Command shall ensure that objects (other than those exempted) are clear of helipads and platforms during take-off and landing operations.
Prior to touchdown on platforms, the Pilot in Command shall ensure that the tail rotor is clear of the helideck floodlights and access stairways. The helicopter should be positioned in such a way that a crewmember has the access stairway visible.
On platforms where obstacles exist close to the northern edge of the Helideck, a black line will be painted across the Helideck on the southern side to assist pilots with tail rotor clearances when hovering with a southerly aspect. With the pilots’ bodies over that line, and with the aircraft in the hover, there will only be 3 meters clearance between the tail rotor disc and the edge of the steel deck.
On Platform X, the black line has been positioned so that with the pilots’ bodies over that line in the hover, the tail rotor disc will be vertically above the edge of the steel deck. On Platform X, there should be no obstructions above Helideck level between the north edge of the steel Helideck, and the "hitching rails" on the main deck. At least 3 meters tail rotor clearance if the black line is used. (Comment: this implies to me that the bum over the circle was not a viable option, and a NS person with his/her SOP would have been in a great deal of trouble. Know the local rules/standard seems to be the lesson. See following para as well).
The black lines are advisory only, and are not intended to imply that 3 meters tail rotor clearance to platform obstructions is considered satisfactory.
Freight on Helidecks
Under certain circumstances, e.g.for manual handling considerations of platform —personnel, freight weighing at least 100 lbs may be left on the NE or NW corner ’ of the Helideck during helicopter operations. All freight on the Helideck is required to be strapped down to prevent movement from wind or rotor wash. The maximum height of the freight is one metre.
The Pilot in Command shall be the final authority for operations with freight on the Helideck.
The Pilot in Command shall ensure that at least one pilot will be able to maintain visual contact with the freight at all times during the take-off and/or landing, and shall confirm with the platform that the freight has been secured against movement.
Helideck Floodlights
Four floodlights are used to illuminate each helideck. These lights, two on north side, two on south side, are situated on the outer edge of the safety netting, and extend 42 cms above helideck level. They therefore represent a significant hazard to tail rotor clearance when terminating on the approach, and in the hover.
CRITICAL PROCEDURE LINKED TO HELIPORT RISK SCENARIO HX08, WHICH IS CLASSIFIED AS LRM.
COMPLIANCE WITH THIS PROCEDURE IS A KEY PREVENTION MEASURE IN REDUCING THIS RISK.
lf in doubt about the suitability of any platform for landing or take·off, the Pilot in Command shall abort the operation until satisfied.