DFC, your example is very poor. You would be somewhere between Farnborough and GWC, chances are you've been transferred from LF to TC.
Most likely the comms failure would come on point of changing frequency (supposition based on my extensive time flying professionally in previous career).
You will be on an allocated squawk with your callsign displaying. LF, TC and En-route will know who you are. You realise you have suffered RTF so you should squawk 7600.
We still hold your callsign and ident but now know you have suffered RTF.
Now the book might say that you continue as Flight Planned in the event of RTF, but
you have not yet been cleared INCAS. Your clearance limit is effectively to remain OUTCAS.
Those flights, that have not received an ATC clearance, should not enter controlled or advisory airspace unless an overriding safety reason compels entry.
Now where is the flight safety implication in a simple RTF?? There is not a huge one. Being 15 miles from Farnborough, with LF and TC knowing exactly who you are, a return to LF would be what I would consider more reasonable to do, instead of flying all the way over the continent, which entails entering CAS when you have not been cleared.
This is especially pertinent because you have just dfeparted LF, know the airfield, know what the weather is, know that they have you identified etc...
The quote above that you have used is not a free pass to enter CAS to join your FP route citing safety reasons, it is there to cover times when, for example a TCAS RA Climb, you have to enter CAS without clearance in order to ensure aircraft safety.
If you think it is acceptable that upon suffering RTF before GWC, you enter CAS without clearance and fly all the way to your destination without RT, then you need to get a grip on reality. Think about how much disruption your flight will cause
If for no other reason think 'security'.
Then think about 'common sense'. 