X3 Roof Rails Rusting !!

[Scooters]

All,
Has anyone else experienced problems with rust / corrosion on the roof rails ?
The rear two curved roof rail supports (curved piece that ataches to the roof) have bubbled under the black protective coating and one has flaked off exposing the metal beneath. - basically rusting from inside out.
The 2004 X3 is out of warranty and the roof rails are not covered under the bodywork corrosion guarantee.
BMW UK customer service basically say tough luck - out of warrantly and it would cost over £ 300 just in parts excluding labour to replace them,

In my view it must be a manufacturing defect with a batch of that part, however, dealership says not qualified to make that judgement, just take photo and forward to BMW UK who say no problem. They refuse to actually have anyone properly inspect it.

Thinking about trying to get media involved.