We run a 12v electric fan clamped to the tent frame to keep us cool, makes a huge difference.Yep not the most ideal piece of kit for European weather, but we sweated our cods off last year beneath a Fibreglass clamshell tent, despite having all the sides open.
Smaller than an Oztent and should be cooler in the heat. oh and you're right, the prices here are nuts!
Has anyone looked at Black Wolf from Australia? The canvas versions (also available in nylon) are simply brilliant - 30 second erection plus another 2 minutes to add a flysheet /porch and peg down. Full head room and warm in the cold whilst well ventilated in the heat (used ours in the desert).