In the presently contemplated example, the cradling member 42 is substantially hemispherical and the anchoring system 44 comprises two suspension members 45 in the form of cords (e.g. at least partially formed from a tendon-like wire or a mash, made of polyethylene, polyester, polyblend, organic material such as tendons, or synthetic material e.g. silicone, Gortex???, etc.) and corresponding ancho