I cleaned the rims a week ago, and the following week, the front rims were covered in brake dust again. I wondered if this is normal for disco's or if my wife may be riding the brakes...

It seems like an unusual amount of brake dust to have accumulated in just one week, but the disco does weigh a lot more than any other car i have owned in the past.

Thanks-

 

It is normal. You can stop some of it from collecting by waxing you wheels after they have been washed.
Be careful what you clean your wheels with cause some cleaners leave a residue that the dust sticks to.
Mike