The easiest part was removing the resistor wiring, this was two wires that originated from the joint where the nearside headlight loom connectors emerge. I cut the wires back to about a centimetre from the loom and put a short section of heat shrink over the exposed ends to tidy them up.
The relays were a bit more complicated as two wires needed joining and the rest removing. To make sure I didn’t remove the wrong wires I started by joining the two wires with a lineman splice and then solder before wrapping up with insulating tape.
The rest of the wires were then taken back to the loom and covered in heat shrink as above. (There is also a fly lead that connects the two relays to each other which comes away with them when the rest of the wires are cut.)
With everything neatly tied back there is very little evidence of the dim-dip system left.