Is it new? If it is I'd be contacting Andrew and looking for a replacement...either watch or free unscratched crystal?
If not then there are a number of people across the forum who will provide an AR service at a small charge, (someone will fill you in on who is the best to go with currently...many have busy workloads and all that!)
Polishing it will definitely get the scratch out...but unfortunately will remove the remaining AR down to bare crystal.