Insurance Bodywork Failure

[Brodes]

Guys,

Please have a look at these images and tell me if you would accept the shade difference between the bumper and the body back from a repairer? Also please tell me if you know under what measurement parameters and values are used to determine what is acceptable for colour difference on a vehicle's panels?

This is the result of hail damage repair from Aussie Hail's Adelaide set up who SGIC assigned to repair our FG XR6T. When I got it back I did have a few other issues which they thankfully repaired no problem, and the rest of the body work and paint job they did looks great, however all the "plastics" where not re-painted which is no problem, however the colour matching is terrible and it now looks like a car that's been repaired with the bumpers, skirts, spoiler, etc. having been thrown on from a faded wreck.
After their re-assessment they confirm to me that it is a different shade, but that their assessor deemed this difference to be normal and that most other cars have a slightly different shade on the plastic body parts, I strongly disagree that any new car comes with shades this different.
I'm still fighting this one ATM and would like to know what you think and if anyone who has been through similar to offer advise.