help with hanging a projector

I am a little confused, just spoke to a friend who works at the white cube, told him roughly what I need and he basically said any cheapo home cinema projector would be enough regarding to the distance (quality is a different issue of course). He's worked out the throw I need will only be 1.4 give or take pending exact measurement...

Yes, projectors come in different types. If it is labeled "pico" then it is a portable/handheld/small one, have to warn you as lots of people sell them on ebay and stuff with dramatic claims of what they can/can't do. Home cinema ones are the next size up(like my one).

When you say the centre of the screen, do you mean the centre point on top of th screen? don't projection project down? Sorry I am a total newbie to projectors... Monitors are more my thing...

Center left to right. If you project from one side and the projector can't adjust enough you end up with a distorted image. Depending on how the projector adjusts for it some will also cut down the image size so you can project diagonal but only at the size of the "smaller" side so it lops off the bits sticking out. Look into "keystone effect" and correction if you need more info on it but hopefully this explains enough.

Projectors mostly do up or down, if it's labeled "desktop" then it projects "up" and you flip it when ceiling mounting(most are done like that). Some do project from the middle but they seemed rare when I looked. I would be ready for needing to place your projector upside down on a shelf, not a huge issue tho.