Same here, got the PFO email last night. I reckon it was the maths side of things that got me.
I actually found the spatial awareness side of things easy enough and the mechanical and other section wasn't too bad.
Might give HR a shout when the fuss dies down and see can they give me a breakdown on where I fell short. If its the maths I can work on that and try again in 3 years.
Gutted over not going to stage two but its made me more determined to get it the next time.
Bill