Fuji
In an OVC004 I would divert to some place with an ILS and a low enough DH e.g. Bournemouth (from memory). In an emergency (below minima for even an ILS) I would pick any ILS with no high terrain nearby, which is most ILS runways in the south.
But if I
had to get into Shoreham under OVC004 (can't see why in reality) I would fly the existing 20 or 02 NDB/DME procedure, as depicted in my GPS database, using the GPS. Much more accurate.
Regards paper charts, I don't think there could be a serious debate as to the legality of flying without them. It's always been legal (Part 91, or UK private flight context). One can debate the wisdom indefinitely, like most things in this business
IMHO getting the FAA to say it is OK to fly without paper charts (if you carry them in some electronic form) is a bit like getting the CAA to say GPS isn't illegal.
I do get Flying, a good mag, but don't recall reading about this.
Homeguard
I too think that there has to be more to this than "can't fly an ILS in IMC if not FM immune". So many flying school planes, and most rental planes, are not FM immune and the CAA would have done a few people by now. They've had a number of years to get around to it. I know it's said that IMC Rating training can be done in VMC but all the smarter instructors do at least some in IMC - as indeed they should.