Do not remove the batting between loft and attic, you may want to add some with a reflective facing toward attic.
Block the wall (gable vent), are there intake vents at bottom under that roof?
Turbine may be pulling air thru the 2 small vents. You want air to enter low and exit high. As neal sed any exit vent will "pull air from the easiest path," use something more rain, heat resistant than cardboard. Painted plywood, foil clad insulation panel. Secure it cause vents will try to suck it off.
You could duct from lower attic thru gable vent area, but it would have to be engineered so as not to make that easiest path, leaving large area unvented.
A long weather shielded "ridge vent" at top of lower roof, with intakes (soffet vents) low would be better than turbine or powered vent, but hot air would rise against loft wall, possibly damaging siding. (Should have looked at smart vent link earlier)
But all that removes heat from that attic, not loft. Is venting space in cathedral not connected to rest of attic? And there's that misplaced vent there too. Need soffet vents below. Smartvent again?
Or joe's wall vents. ( hello, joe, whadda ya know? fancy meeting you here. I got here by US mail, poor mike
These folks will soon be sorry.)
But loft is still heat trap. heat from room rises, can't circulate due to half wall. Do those windows open? Of course not who would want windows that open? Vents thru wall above windows, dampered, thermostatically controlled. But will loose heat from room. Fans above wall, not ceiling fans, to push air back down or fans in loft floor registers would help circulation.