Found this while looking for upgrade options for my low beam which is sub optimal (or crap, which ever you prefer).

If I am reading this correctly its pretty much plug and play connections to a large can relay(with fuses) and just one battery lead to wire in and connect. Just plugs onto the H4 beams and has one plug that goes into one of the existing headlight wires to switch the relay. The kit was originally intended for Landrovers which enjoy the same dim headlight/power through the switch config as early Jags. You can do this prior to upgrading headlights or at the same time. Thought this may interest those not wanting to get into wiring too much.

Headlight Wiring Upgrade Kit | TRAXIDE - RV | Traxide - RV

Narva also have nice sealed beam replacement kit.

Narva 7" H4 Conversion Kit - Supercheap Auto Australia

 

Thanks Steve, good info.

FYI, your link to the Narva conversion is corrupted..