Toad Immobiliser fitting to TD5

Hello everyone. I'm new here and fairly new to Land Rovers! After two years of owning a 30 year old 90 300TDi, I've traded it up for an '03 plate 90.

I'm looking to make it a wee bit more secure etc! I've a brand new - un-fitted Toad Sterling Touch Cat 2 immobiliser which would make sense fitting. I've been over the installation instructions but looking for any member advice before I go cutting and soldering wires.

I've attached a couple of screen grabs from their instructions however can anyone point me towards the best wires/connections to use and their best location. It is the connecting of the BLUE and WHITE wires I'm unsure of:

BLUE - 'starter motor isolating circuit [18a relay used for this circuit].
WHITE - 2nd isolating circuit [18a relay used for this circuit] This circuit must be live during cranking and engine running.

Any advice greatly appreciated.

Thanks, Iain