I have never indexed these banns before. Am I correct to assume no parish name given when all it says is "this parish" since there is no clue what book this came from? Middlesex must be too broad an area for one parish.
The Field Help tells us: "If the locality was not recorded or was written as a variation of the word "unknown," press Ctrl+B to mark this field blank."
So, we must leave it up to the researcher. As you have observed, the parish name was not recorded on your image.
Am I correct in assuming that since there are no Entry numbers on the parish records themselves that i should proceed left to right down the page for indexing order?