apparently there were green light signals from the Tower but I wasn't looking for them
Yes, I once discussed radio failure procedures with the Cambridge controllers - I asked them whether they had a clue where to look for the lights, and after some joking about "weren't they in that cupboard we cleaned out five years ago" they agreed that they did actually know where to put their hands on them.
Answer 'Oh, you mean the one with the emergency landing ?'
I think that actually they luurve "emergency landings" at Cambridge, gives the fire crews something to do.
I've had the fire trucks sent out for me at least three times, and on none of these occasions was I concerned that I had a serious issue.