Last year, GFA applications needed to be in by 13th July and the forms returned by 27th July.
A Shewsbury result *should* be fine, especially as they haven't even announced the application dates yet. I did hear rumours that they'd be switching to a online application system this year, which might mean an even later entry date.
I'd enter the ballot anyway if your GFA time is not already in the bag. If you get your planned time next week, the GFA entry is guaranteed and will just replace your ballot entry.
I know of people in the past that have entered the ballot, replaced that with a GFA entry in August ( when GFA entry ran through until September), and then with a Champs start the following January.