In case it helps anyone doing the mod, I did it recently and these are the parts I bought:
https://www.autoelectricsupplies.co.uk050205 (2.8 mm female spade - goes into the wiring loom instead of cutting wires)
050502 (90 degree h4 headlight connector - you only need one out of the pack)
100206 (waterproof fuse holder so you can take it out at MOT time to disable the mod)
100503 (glass fuse for the above, they only sell 10 packs)
010102 (cable)
Cost about £14.00 delivered, but I couldn't find it cheaper on ebay or anywhere else
2 solder joints and splice in the fuse and the job's done.