Hot and cold pipe

Low level with the hot pipe above the cold pipe. The reason is because if the pipe leaks its easier to access and will be minimise the damage.

It’s completely up to your personal taste and what the room is used for. You could run them in the ceiling or chase them on to the wall. You could have them low level if you are happy with them being on display, or you could change the skirting boards to allow for hidden pipes. Run the cold at the bottom and the hot on top, this is to stop for the cold pipe being heated by the hot tap and make sure it’s clipped.

If you are to run your pipes below the floor if a leak was to accour you would have to take said flooring up witch could be a costly job. Through my experience it is cheaper to repair a ceiling that to replace flooring so I would recommend running them in the ceiling or running them low lever in the wall with the hot above the cold pipe so the heat from the hot pipe doesn't transfer onto the cold. Any pipes run low level in a wall should be run above 10 inches to avoid getting pinned by a nail when skirting board is fit.