Where do i start with putting a new window in my bathroom. i will be bricking up the current one first and then moving it 70cm to the right (if you get what i mean).

It is a solid, non cavity brick wall 235mm thick. The opening will be 640mm and i intend to use one prop with an eye holding up the brick work above the new lintel.

So after i have propped the window how do i go about it?

Do you insert the lintel first or do you do the cill first and then work your way up taking out the bricks in the way and making good the sides?

What he said.

Since it's only moving 70cm my guess is you may have to take the old lintel out before you can get the new one in? If so the unsupported length might be too long for just one prop? I guess you could prop, remove the old lintel, brick up the old window, move the prop along, install the new lintel, remove brickwork under new lintel.