You beauty, the front hubs aren't magnetic !!
That's saved me a job, I'll just give them a light coating of waxoyl while I've got the wheels off.
I will paint the 'bell' section of the front discs though, as they look grotty through the wheels.
The rear hubs are 100% magnetic though, as I just double checked them.
They got 2 coats of hammerite smooth and then a coating of waxoyl. Rear disc 'bells' got some paint too.
The photos I took are really poor, but I will see what I can do