Rear brake disc conversion problem - help needed

Hello - everything was going well until I fitted the discs. There is a paper thin clearance to the carrier on the back side. The anti rattle shims do not fit which is not a big deal.

The disc rotates but I am not happy with the clearance. I have bought Brembo 08.5005.14 discs which are suitable for;

VW 191615601
SEAT 357615601

It measures 40mm from the front face to the disc part. See the attached photos.

I have compared the carriers to an old set I had from a mk2 and the new vs old are the same.

The bearings fit well.

I am using Meyle 100 501 0011/12 hubs.

Bearings are Febi 03764.

What is the problem?