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I agree with 130cm being a bit cramped, unless you're both 5 foot 0. We've got a 150cm and it's fine, any shorter and it would be uncomfortable for me.
The first thing that I can see there is that the bath will get constantly sprayed from the shower. With London water that's going to need cleaning very regularly.
We got a standard shower tray installed flush and I haven't regretted going that route over wet room tiles. Others may disagree.
And this is the mock up
Wife has found a 130cm long bath she thinks will fit
not sure about toilet positioning
there is a 2nd toilet in the flat