It's not every day that three authors are proven wrong at once!
So Hilary Doyle did get it right. Goes to show that one needs to check their references, then check them again....and again. Sometimes one just needs to find the right photo and it changes everything.
Thanks for the confirmation Jack!
Funny that the war-time, German-made drawings on page 52 of Spielberger's Panzer I and II are wrong, I busted out the micrometer and they are not correct.
For that matter, Doyle's 1973 side-view drawing of an Ausf B on page 50 should show the staggered barrel lengths superimposed on each other, (at least as a cut-away view) but since it is a left-side view, it instead shows only the one barrel. If it were a right hand view, it would show this important detail.