I also have a LHD mk1. Use these guys.when it co.es to electrics, dont cut corners. Get new electics and have it all professionally installed. Do t have your pride and joy coming to a halt or worse, going up in flames trying to save 100 quid.
https://www.autosparks.co.uk/fd295-ford-escort-mk1-rs2000-engine-bay-harness.html