New drainage on a concrete slab

Hi all,

My IP settled last Wed :D and Ive got work starting already. Im creating a landry area which is adjacent to the bathroom. The taps for the laundry tub and washing machine arent really a concern as there should be pipes running through it for the shower.

The drain however is a different story. Im assuming of a plumber is to fit a new drain in, then the concrete needs to be dug up to connect it to another drain (ie floor drain in the bathroom?).

Another idea, which Im not sure if its possible is to have the drain pipe running along the back of the laundry space at floor level, and then go out and connect up in the backyard somewhere?

Any ideas?
Nah doesnt really run to a external wall.
Green shaded area is where I plan to put a laundry tub and red area for the washing machine / dryer etc.