Depends what you mean by a few millimetres, if it is literally only 2-3 mm I would be tempted to extend the slot for the brake pad by that amount using a small round file.
Ooo, that could be an ace bodge. Will look closer tonight - roughly bunging the pads on lost night and the brake wasn't centred, it looked like one pad was just about ok on the rim, and the other was kind of half on the rim, half rubbing the tyre.
Depends what you mean by a few millimetres, if it is literally only 2-3 mm I would be tempted to extend the slot for the brake pad by that amount using a small round file.