161 flew Whitleys until late 1942, then Halifaxes from 1943 to 1944 when they converted to Stirlings. My father was a pilot in 161 from late 1942 to late 1943. I’ve checked his logbooks and Geoffrey was never a memeber of his aircrew. 161 also operated Lysanders. At a push they couls carry 2 passengers.
But if he took over control of a Stiring when the pilot was incapcitated and it was on SOE missions it must have been from mid 1944 onwards.