The front and rear lights all need wiring into block terminals so that they are compatible with the Westfield loom. I have bought a tool suitable for crimping the tiny uninsulated needle terminals from Vehicle Wiring Products.

http://www.vehicle-wiring-products.eu/VWP-onlinestore/terminalsnonins/noninscrimps.php

I just snipped the original terminals from the lights and followed the Westfield manual instructions. It's actually really neat how the block terminals are made up.

I started on the rear lights and repeated the process for the fog light and the front lights too. Once I'm happy they all work I'll cable tie everything out of the way.