Bought pads from Amazon said they fit
I compressed all 4 pistons on my calibers and only on pad will fit in on either side. So I removed the entire caliber and put bith pads in and tried to slide caliber back over disk and the opening between pads I can eyeball and see its too narrow.
Could the pads be too thick?

 

Note that the brakes changed at VIN G45704.

What are the pads you bought, and how much off fitting are they? With the OEM pads on my pre-G45704 XJ6 it is a tight fit if the discs are new but they will fit with perseverance.

You may find the attached useful.

 

On my 06 SV8 I had similar issue. I discovered that the caliper rewind tool needed an xtra 1/4 turn to make the clearance for the tight fit.
For what it is worth, I have an early VIN H00099 with Akenobno Euro pads 1095 on the rear.

 

It would help to know year model and possibly vin to identify the correct pad.