Hi Jim, hope you're well,
You need:
1. Pressed number plates from UK company. The link is on original write up. Send them what they need (proof of identity, etc.) and they'll send you aluminium pressed number plates. No need to go there. Use Royal Mail services.
2. Surrounds from German company carsign.de They will send you the full kit which includes special backing plate. I have no picture of that backing plate, but it is included for both front and rear frame/surround. The backing plate is not visible when installed. Those German surrounds marry with metal pressed number plates from UK company perfectly well, although those companies know nothing about each other. However, UK company use original German equipment to manufacture metal pressed plates. This guarantees precise fit. You will need to send CarSign money with international bank transfer. CarSign will DHL you the parcel.
3. Stainless steel screws from Halfords. See detail picture. I used about 10 screws per number plate, so purchase 20 screws. You need to drill small hole for each screw.
4. Front plate come custom bend, but they will both needs some additional 'adjustment' bending when installing on car. You can do it with your fingers when you install the kit. (I was first customer who supplied them measurements of number plate niches for A8 D2
Once done, the quality of this stuff is just amazing.
P.S. You can order custom "inlay" at the bottom of the frame only for your front bumper since rear number place niche on D2 is too tight in terms if vertical dimension.
Hope it makes more sense now.