Thanks All, turned out to be a more interesting discussion than I thought it would be.
JohnV6 - Saw your post and I intend to do the same and re run the test.
Rog - That thermal image shows the very hot pipe that feeds the heater matrix, although not the same engine I think it's highly likely mine is the same. Hadn't thought of discarding the Intake Box but have seen another thread where someone has fitted the filter just in front of the throttle body on the left (cooler) side of the engine bay.
RichardV6 - interesting taking air from the bonnet side vents, food for thought.
gomog - you are correct in assuming the car was not moving and I was IN the car. I did put the top down as the interior was 2 degrees warmer than Ambient when I got in.
Montegue - Interesting you and Rog both placed the air filter high at the back of the engine.
I'll need to take some temp readings from possible air intake locations in the engine bay while driving to see where best to take air from. Agree that Intake temps at Idle aren't relevant so will have to figure out how to monitor on the go, it may be that where its currently located is ok when on the move.
