How should waste pipes exit a dorma loft conversion?

Hello
I've recently bought a house that has had a loft conversion done over 15 years ago.

The en suite in the loft contains a shower, sink and loo.
Currently the waste pipes for the sink and shower link together and then drop through the floor into the bathroom on the 1st floor. The waste pipe from the loo also drops through the floor to the 1st floor bathroom.

Both waste pipes running down into 1st floor bathroom are boxed in and run down the wall of the 1st floor bathroom until then bend near floor level and then join to the loo waste pipe and sink waste pipe from the 1st floor bathroom.

My dilema....
I would like to install a shower in the 1st floor bathroom but the boxed in pipes coming down from the loft en suite are in the only place that a shower would fit.

Is it possible for waste pipes from loft conversions to exit right at the top of an outside wall or do they typically run down to the floor below and exit from there?

I have the option of still having the waste pipes run into the 1st floor bathroom but then run them along close to the ceiling and then drop down another wall (thus giving me the space for the shower). However, if there is a solution specific to most loft conversions I would be interested to hear?

I have (hopefully) uploaded a pic. As you can see, it's a typical (if not large) dorma. The en suite runs from the left hand (play school style!) window to the left hand edge of the dorma. The 1st floor bathroom is underneath it where you can see most of the (multicoloured!) drainpipes.

Thanks in advance.

Yo can get slate pieces that take pipes out but it would look terrible on your property and im not even sure itcould be done.The ceilling option may work but you eould need the correct run and probably rodding access points.Best to get a plumber in to measure up.

In the meantime i dont think that sink it fitted to that soil stack very well might want to get looked at too

It`s not good that soil/vent pipe should go right up the front of the dormer and 900mm above the top of the window. Then pipes could go into it Still wouldn`t look great