ok got it done, was really easy.

supplies:
1. "permanent mount" from amazon
https://www.amazon.com/gp/product/B01ATTRLJE

2. mirrortap 15" mtx rj-11 power cord
Blendmount.com - MirrorTap Power Cords
coupon: BlendMount | J28 Design Inc. - Friend Offer

process (refer to post above with drawings):

1. remove bolt from sunglass holder [believe it was a torx]
2. lower down the overhead light assembly, gently pull down from where you just removed the bolt.
3. gently pull out trim piece to expose wiring harness that powers the "interior mirror"
4. use the largest set of taps (from MTX power cord kit) and tap into pin 1 (power) and pin 2 (ground) on "8 pin" connector [test your vehicle, it may not be same as mine... power was black/green and ground was brown wire]
see attached pic and I would strongly suggest you verify with multi-meter before doing it to your car. I wrapped the connector/taps once around with electrical tape to prevent them from pulling out, even though they were pretty snug.
5. route the thin power cable out of the seam of trim piece and reinstall (no need to cut trim or anything)
6. bolt the overhead light back up
7. mount your radar detector to the windshield with the double-sided tape "permanent" mount (it's not really permanent, but it holds it well), position high and tight and you're done.

oh yeah, don't cheap out and buy the power kit off ebay - the taps that were on that one were a little too small and didn't connect reliably. I bought that one too and ended up wasting 9 bones... just go w/ the better quality MirrorTap :)

I assume this is a switched power supply that turns off with ignition? This would work for my dashcam which is installed in the same area, but I could only get a perm supply, so always on, but I need both a perm supply and switched plus earth

Yep it is switched, only thing I'd check is that the power requirement isn't much greater than a radar detector... But I wouldn't expect it'd be a ton more. The power cord has a 2-amp fuse inline.

Thanks for this, was a great help. I used the wire on terminal 1 as above and used the earth stood above rather than terminal 2 and works great. Really easy as well.
Thanks again.

This is awesome. Thank you for doing this!

Thanks pardz!

I used pin 1 (black with purple stripe 12V) and pin 2 (brown ground)

Attachment 72398

Mirror Tap ValentineOne install
 

Completed this mod early in the morning, what a beautifully clean installation, thanks all for your input on this topic.

Next: I may be lowering the car using the VCDS, i've already done most of the other VCDS mods.

Don't know what my long-term status with this car will be, as it is a diesel and who knows what October will bring from Volkswagen Audi Group!

The amazon link says "Not compatible with escort max series" Is that correct?

Thanks for all the info and direction. Super helpful.

Great write-up. Thanks!