Right !
i can feel @Nickfromwales breath on my back already !
In the below ground domain we are having a wc .
Its quite possible it’s location downstairs has to be moved .
It will be under the parking area and on the opposite side to all the drainage ( typically ).
As it stands the macerator would have to pump up 2 metres - then ‘around ‘ the stairwell , then horizontal for maybe 8 metres , then possibly vertical again ( less than 1 metre ) !!!
Directly below this ‘exit’ point is the below ground kitchen sink ( which of course has a macerator) . I’m assuming the run for the wc is too long and convoluted ( diagram might help ) . So ! Could the wc macerator feed into the kitchen one to ‘eject’ waste ? ???