Mum of 3 - have you looked at the new admissions criteria for DGGS? If Wilmington falls into one of the listed parishes then I think you should be ok. However, I think we are all aware there are no guarantees so its good to have other schools you're happy with on the list "just in case"
My DD also wants to go to DGGS, and failing that she also likes Wilmington. She wasn't so keen on Newstead but we have decided she will sit the test anyway and have put this choice lower down on the list. Where we are, we have very limited choice of good schools she can reach easily.
You obviously also have the choices of the Bexley schools which I'd assume are equally accessible to you?
I agree, it is so much stress (I thought it'd be easy after the 11+ results
) but as soon as we made our decisions and submitted our CAF is was a huge weight off my mind. Nothing more to do now except wait til March. And appeal if necessary ...