on the oil tank behind the rear light there are two inlets/outlets.
am i right in thinking the one closest to the rear light is the return, and the other (slightly higher) is the breather?
also does the pipe from the coolant expansion tank go to the top of the radiator just by the cap?
Yep that all sounds about right ,
If you need to check you've got it right.
The oil return pipe is allen bolted to the engine to the rear / under of the starter motor and fits nearest the tail light.
And the oil tank breather is the closest to the cylinder ,small dia ,and nearest the dip stick..
You might want to replace the coolant pipe as the original ones are total cr@p .