En-suite loo position - an unholy convergence

[MortarThePoint]

I know all of these sorts of things should be worked out way in advance but... I am struggling with the placement of the loo in our ensuite. There are a few pipes that need to converge to then pass through the concrete slab floor (first floor). 2no. 100mm toilet pipes and 1no. 40mm shower waste. The overall size of the ensuite if 3000mm x 2450mm. The ensuite layout basically comes down to two options shown below.

 

I am laying the UFH (water based) and need to finalise the position as to keep both options alive but than risks cold feet whilst sat on the loo. I can't get the UFH pipes to close too the area where the toilet mounting screws will go as that's a recipe for disaster. I have shown the current UFH planned area in green in the layouts below. I don't think I can extend the pipes to create an area to heat the right foot in the second layout due to the mounting holes of the toilet.

 

I think the second layout would need a T-junction mounted on the rear of the ensuite toilet (see image below of what going in where) and there would be a minor heights issue as the other toilet's waste will need to have dropped due to pipe fall, but I think that's only within tolerance though so should be fine. I'm not sure how I would join the shower waste that's coming through the wall though. I could just send it through the hole in the floor and join lower down which is where the ensuite shower  and bath wastes will be joining having passed through their own holes in the floor. I may have to have push the loo away from the wall and have a box that goes as high as the top of the ensuite toilet cisten to buy some space (?)

 

Holes quite forward: https://www.victorianplumbing.co.uk/burlington-close-coupled-wc-ceramic-lever-flush-bur-p5c1

 

Holes towards the back, perhaps 300mm forward of wall: https://www.victorianplumbing.co.uk/melbourne-ceramic-wc-pan-cistern

 

RED: 110mm soil pipe coming from toilet mounted on other side of wall so at it's exit height. 

BLUE: 40mm shower waste pipe coming through the wall at a height of "in the screed".

 

 

 

 

[MortarThePoint]

Some photos. In the one from above you can just see a line 450mm from the side wall and a second 450mm from the top wall. They mark the edges of the currently proposed UFH layout (green in previous post).

 

The second photo shows a pen X on the wall which is in-line with the waste of the toilet the other side of the wall.