I will try to help as much as I can.
My cable to raise the lights got broke by a clumsy bodyshop. I, also, have nothing that prevents the bonnet opening with the headlights raised, so can't help you there.
Regarding the control valve; yes there should be 2 vacuum pipes coming through the grommeted holes and the pipe from the rear of the car going into the top. The control valve sits on top of the 2 headlight pipes, with 2 bolts through the inner wing securing it. The metal pressure release valve points towards the front of the car, with the 2 electrical connectors (I'm an expert in this area now!!) underneath it.
The bonnet prop should in no way foul this, but be attached just in front of it.
Sounds like the bonnet prop has been fitted incorrectly.
Here is a picture...
Hope this helps.
Antony