I agree that this is what is probably concerning them. Do you have any ways to prove to them that your relationship is stronger and better with Annabel than with the previous girlfriend/s? If they sadly refuse, then you will need to think of ways that will show them how close & genuine relationship you have and maybe make another visit to see her (that should satisfy them more that it is more genuine) before applying again sometime later, but how long to leave it before applying again, I don't know.