You're right - the turret is throwing me off as well. I still thinks the chassis is a Mk IA, how about a Befehlspanzer?
Didn't want to double post but I think I found something -
from
http://www.achtungpanzer.com/pz11.htm
"During Spanish Civil War, PzKpfw I Ausf B was experimentally armed with Italian 20mm Breda Modello (model) 1935 light anti-aircraft gun mounted in a modified turret, in order to increase its combat potential. Some sources state that three tanks were converted that way."
and by the looks of the headgear and uniform of the one person in the pic I think that is what we're looking at.