It's been a while since I read it, but flicking back through only two cases jump out: in "A Tragic Landing" and "Train-Busting", and in both cases it's a damaged aircraft coming in to land.

The pilot's oxygen mask and radio were plugged in to the cockpit so had to be disconnected when bailing out or ditching ("Every endeavour should be made to bale out rather than ditch. If flying low over the sea the aircraft should be pulled up to gain as much height as possible. On the climb undo helmet and disconnect R/T plug. Jettison hood. Do not release harness until bailing out has been decided upon.", Pilot's Notes for Tempest V). It's not specifically mentioned as part of the procedure for a forced landing, but if a pilot was concerned about getting out as quickly as possible they may have done so prior to starting their approach.

As Clostermann wrote Le Grand Cirque in French I wondered if there might be a translation issue, digging out a French version it looks like "Too late, he had switched off his radio" was originally "Trop tard! Il a débranché sa radio", and Google Translate suggests "unplugged" is a better translation than "switched off". Turning off the radio wasn't, as far as I'm aware, part of landing, so it seems more like a couple of isolated incidents.