The two browns/reds are joined together in a separate connector, and are the permanent live which feeds the pull switch.So the live from the toilet light fitting goes to the bathroom ceiling rose loop in, is that correct?.
With the power off, at the toilet light connect the two browns (or reds) in a connector on their own
Not sure what you mean, are these not needed.
What goes in to L1 on the 2 way pull cord switch.
The live for the bathroom light comes from the switch (blue or black)
The remaining blue or black comes from the bathroom, and is the neutral for the toilet light.