Stunning photos!
As you say Washout, surprisingly little or no Rudder/Aileron in an assymetric condition.
Only suggestion I can come up with for that is; maybe nos 1 (and 2 if running) were at very low power and the aeroplane descending at a relatively high airspeed, i.e. loads of airflow giving effective controls hence little input required and little or no thrust, minimising yaw.
I imagine the photo was staged, but there are recorded instances of uncommanded featherings of Merlins (albeit on Lancasters) happening. One to an ATA pilot (Jeffrey Wikner) but Centaurus, who posts regularly on PPRUNE wrote about such an incident he experienced of it happening on a Lincoln - also Merlin powered.
Still, bet they were happier when they were started up again!
BSD.
I believe Guy Gibson had the same issue ,flying some bods from the air ministry on a Lanc demo flight.
They were flying on one, when his FE feathered that one as well, IIRC