I haven’t tried that but I did try something a little simpler. I dropped both Pawns into the scene in the editor. I then created the attachment in the Level Blueprint between the Turret and the Hull triggered by the BeginPlay event. I was able to posses both Pawns but the turret remained stationary whilst piloting the hull.
I thought maybe I’d configured the Attach node wrong but I tried every available permutation to configure it but still got the same behaviour every time.
I’m getting the feeling my initial attempt didn’t work because the child actors only get spawned at runtime. Having set the reference to the child pawn up in the editor may essentially have created a reference to a temporary actor that ceased to exist when the simulation started?
Update: Came across this on the roadmap - Trello
Looks like I’m going top have to wait for this to be properly implemented.