Best place to site a sink..

[Wingedharpy]

Would you good folk settle an argument DH and I are currently having?
Does a bathroom sink have to be put on the same wall as a loo, for drainage purposes, or not?
Many thanks.

No. None of ours are.

Great!!!
I win

No, none of ours are either.

No. However, there must be a sufficient angle on the waste pipe furthest away from the main waste to ensure proper drainage.

Our sink is opposite the waste whilst the toilet is next to the waste. No issues. Previous owners installed a shower next to the sink but hadn't angled the waste sufficiently resulting in leaks that affected the walls below it.

I'm not sure I understand any of what you've told me acatcalledjohn, thought I'm sure it's crucial stuff and I believe you.
How do we ensure we have "sufficient angle"?
Does it depend on the height of the sink ?
Does it depend on the style of the sink chosen?
We know nothing (as you can probably tell)

That's the bit a plumber should know and sits under the floor boards. I don't know what the angle should be, but I do know that you rely on gravity so when it's too flat residue and hair build up much more quickly causing blockages and subsequent leaks.