Hi Peter,
I had gone as far as I could in restricting Engine Bay Air into the top of the Heater Box but the entry air was still significantly Hotter than Ambient, so I wouldn't fit a Bypass if I were starting again, I'll have to decide on removing the Bypass but no rush at the moment.
BTW. I proved Rogers idea of extracting air via the Heater box today. Fitted a cheap £5 fan mounted in some foam, lit a Smoke Match in the passenger footwell and watched it pull the smoke out and up through the heater box.
Lots of little problems to work through before I have a proper implementation though.
