I can't find the AW.105/T rivits available to attach the chrome U shaped trim on the rear panel of the Trunk lid. If I can't come up with some creative way of doing it I plan on taking a appropriately sized round head machine screw, grind slightly two opposing flat spots on the side of the heads, bolt them in with a really small washer so the head stands proud slightly, intall the trim, then turn the screw from the inside (off the flats and onto the full head width). Anyone got a better idea?

BD.26706/2 looks awdully long. What does it attach to?

Mine didnt have rivets if youbare talking about the number plate surround, it has small bolts that can slide around in back size of the chrome but cannot spin, if that makes sense... then a nut attaches inside the trunk lid. Bit of a pain to align everything and get nuts tight without the chrome shifting.

yes the license plate surround or "frame".

some of these frames have pins in the back that are part of the frame and you slide a tight vinyl bushing over the pins to secure the frame in place.

you might be able to find suitable bushings or "sleeves" from Bungee Cord Hooks, or from previous Jaguar models starting with the MK-2, the MK-X, the S type, 420, 420-G, or Series 1 XJ thru Series 3. They all have similar frames.

When I repainted my car, I removed the license plate surround and misplaced three of the screws and nuts.
I went to ACE hardware with the remaining one and matched up machine screws.
Using the existing one as a template, I filed the machine screws so they would slide onto the surround. I made them a little tighter so they would not move as freely as the originals and they worked fine. If you look at the surround, you should see a slot at the ends where the screws are placed into the surround.
My car is a Series 3 and I guess yours is not. Your attached diagram looks like 69-74 Series 1 or maybe an early Series 2.
Search Part # BD26706 Rivet.

Yup, that's exactly what I'm doing. Many thanks.