Ignition Switched fuse or wire in the rear back cargo area?

[DriverX]

Hi fellow X enthusiasts,

I'm going to wire up a rear "dash" cam. Just too many close calls recently with pure idiots on the road. I am stuck trying to find an ignition-switched source in the rear anywhere.

Any ideas?

I can't find a nice cheap voltage cutoff 12v to 5v USB that will cutoff the voltage at what I want (more than 12.4V). Plus it would be a lot of uneventful recording on the SD card while the car is parked in the garage. I guess I need it more for idiots on the road than idiots in the car parks, so not too interested in parking monitoring at the moment.

I've checked all the fuses, as well as any floating harness stuffed in either of the rear side compartments and can't find any ignition-switched ones. Everything I have found pulls 12v with the car off (even after the 15-20 minute cooldown on the canbus system).

Any help appreciated,

Thank you!