I married my husband and he flew back to the UK afterwards while I stayed behind and applied for my visa. I had it in 3-4 weeks time, and I took my time putting the application and documents together and doing my biometrics appointment, etc. It isn't that long to be apart in the grand scheme of a lifetime together - it just makes you appreciate each other more once you are together for good! So if you do have to head back and can't wait around for her visa to arrive, don't let it upset you too much. It might be good for her to spend a few weeks with family and friends while she waits for the visa anyway, and there is always Skype! It's not so bad to use it when you only have to use it for a few weeks time. Most people here had to spend a year apart or more before being able to be with their loved one, but it all worked out in the end.
Good luck!!!