PJ...
<<considerable training to convert between left and right seats in the commercial world of aviation>>
No actually...
At Big Airways, if you are changing seats same type (R -> L we hope) its 4-6 sims, and maybe 15 sectors (in shorthaul). By far and away the majority of that is "command training", not getting used to the other seat itself...
<<Presumably the co-pilot would have had to fly the left seat for the remainder of this flight>>
No! He would have remained in the RHS.
At BA, all aircraft have NW tillers both sides. For those airlines where not, then tough - he'd have to land it and block the runway... NWS not used on the landing roll - not until you want to taxi off.
<<What kind of training do first officers have for events such as this when technically they are only qualified to be in control from the right hand seat?>>
Both pilots regularly practice "incapacitation drills". Firstly to remember to try and notice when he's "gone"! Surprising how long it takes in the sim, say doing an auto approach to notice he's not said anything for a bit, and then look across to see him slumped over (and grinning!). Secondly, to practice taking everything slowly and thoroughly, and get on the ground, with all the SOPs scr*wed up, since you're by yourself...
ATB
NoD