Hot wiring any old car (or old design) is the same. So leaving out specifics of anything "Defender" if you loose the ignition switch for some reason, and you still have your key, you have to duplicate what that switch does, and that is giving power to the ignition, and for a moment... the starter relay. If you look at the back of the ignition switch you can figure it out in a heartbeat. If you want the specifics of what wire goes where or what color is what, then the best thing to do is not post that info here and have a look in your service manual and you'll see what needs to go to what easily.
Power in (12v) needs to go to power the ignition and then you need power to bump the starter for a moment. Same in a 1957 Chevy as a Defender, so no "theft" info. posted.
I do not check PMs. Call or email if you need something.
ECR is not a parts source. We are not in the mail order business.