If the scratch has gone down to the primer or the bare metal then there is nothing really you can do. T-cut will only take out some small scratches. Colour magic can cover some scratches to an extent but washes straight off when you wash the car again. Probably best to use a company that specialise in stone chips and small scratches. They are mobile companies and will usually come out to give a free quote. If you have one or more cars it would be beneficial to get them done together for a price reduction.