That resolves the issue, thanks for your help 
(I have hence accepted this answer).
It’s pretty much identical to the screenshot of the Actor-derived projectile Blueprint shown above, at any rate, this issue has been resolved.
In all fairness though, you are correct in that the actor is not ticking, but not because PrimaryActorTick.bCanEverTick is false, instead, that Super::BeginPlay() had not been called in the version of that method for AQTBDWeaponProjectile.