blue up
If you are still intending to remove the major components, I would suggest you must get the correct tools, slings, and stands to mount the bits on. With the amount of Wessex in service with the RAF, Navy, and Bristow, I would think that there must be some surplus gear around some where, unless its all be scrapped.
The Wessex is not a light aircraft, and these components are heavy, and will cause injury if mishandled, and I would suggest you need at least one person who knows what they are doing.
The head sling is a light cable assembly, with a loop for a shackle, its will not take the weight of the head and gearbox in one .The gearbox is slung from the mast, with a screw on fitment, and an eyelet.
I have no wish to put a damper on your project, but health and safety will not be impressed if you use the wrong gear, and I am sure you value having all your limbs intact.