Now that Alan has adjusted and repaired the general layout of my mesh, I've began to define the eye.
The eye is getting there gradually, although it needs to be polished a bit. I think this may be best left until I've established the general appearance of the other facial features, otherwise I feel I may end up having particular features which don't sit well with the others, i.e. super refined eyes next to a soft and stylised nose.
The mesh is still pretty untidy, but at least the right loops are in the right places. I think some digital rhinoplasty is the next logical step.