Don't sweat it too much - on your 98 Disco the electrics are mostly another company called Rists. If you were to carry anything electrical, a spare ignition amplifier, and maybe some HT leads would be good.
The legend of Lucas, the Prince of Darkness refers mainly to the wiring and components of 60's, 70's and 80's British vehicles made by the Lucas company ( Lucas - Prince of Darkness - Lucas Electrical Humor Jokes ). By the 94 update LR had their act (mostly) together and that era Disco's are pretty good. With the exception of relays to drive headlights, Disco 1's don't seem to have problems except if you go swimming in the car.

