Another option would be to buy a paint chip repair kit from Dr Colourchip or Chipex.
I used a Chipex kit on my mk6 GTD. The colour match (Carbon Grey) was excellent and with time and practice, you can get good results. If you're not happy with your efforts, you can used the blending solution supplied in the kit to completely remove the paint you've applied without damaging the surrounding paintwork and start again.