No need to apologise. I've done jobs in Sligo before, but like you I agree it's too far for most things. About a two hour drive to Sligo Town from here.
Brown & Earth from the luminaire. Twin brown between switches. Single brown from last switch to luminaire switched phase connection. Other methods are of course possible.
No. Logic tells us that 2 wire high current testing is always the better measurement to utilise. Low current loop testing is simply a compromise due to the use of residual current devices.