Toilet and sink do not make it a special location, only bath and shower does that. Any fuse will get warm, that's how they work, the metal inside melts when it gets too hot due to excess current, so it needs to be in free air, any panel would need vents to allow passage of air to cool it, which in turn would also mean any moisture in the room would also be flowing past the fuse.
The conduit would need earthing and since before the meter that is down to the DNO, so toilet and sink not really too much of a problem, but as bathroom fuse likely needs moving and since DNO must do that likely expensive.