Ignition live for aux fusebox

Hi all

I'm going to fit an aux fusebox in my TD5 90, thinking under the drivers seat with the ecu.
I want permanent live, and ignition switched live on a double bus fusebox.
I'm ok with the permanent live, but the ignition switched variety I would like in the easiest shortest way possible.

Any ideas please of where to pick it up from?
It will be for things like day time running lights, immboliser etc.

Thankyou

Infact been as there is no ABS or air con. Can I come off the underseat fusebox for the permanent live?

Live feed from brake light feed to relay triggering feed from battery through 30amp fuse?