Hi Both:
Not sure this is should be a coading priority, but in any case ...
I do actually know of one case in which a Mossie returned under the control of the navigator, after the pilot had died. Rather tragic tale of a P.R. crew on the last sortie of their tour near the end of the war (30 April, 1945 as a matter of fact).
MM333, a PR. XVI, was hit by small-arms fire during a low pass over Rhodes, and the pilot, Ron Watson, was struck in the abdomen. He realised he was hit, and asked the Nav, "Kev" Kevan, to "take her home and prang her." (Going from memory on the quote.) Watson slipped in and out of consciousness on the return journey and eventually died.
The nav managed to fly to Lydda, now apparently Ben-Gurion airport, and belly-land the aircraft. He was unable to reach all the controls, as some were on the far (left-hand) side of the cockpit. One source says the controls in question were the flaps and undercarriage, but not having a diagram in front of me I can't swear to it.
The aircraft touched down but bounced, going off the end of the runway. However Kevan escaped from the wreck unharmed, with pictures intact.
There's also a couple of well-known episodes of Navs briefly taking over control after their pilot had been blinded, generally by exploding targets.
Like I say though, not sure HT should make this a priority.