Seems it is based in an assumption that Maria Searle who married Abraham Brown (and he then died) is the same person as the Maria Brown Searly who married James Gorman (she a spinster).
Was James Gorman a bachelor, or widower when the married? The reason I ask is that I am just wondering if James was his child all along, from a previous marriage. If Miss Maria Brown Searly whom he married was single and from Dorset, then Francis born 6 or 7 years earlier in London (yes, have I got that right, Francis was bn London?) is more likely to be his child from a previous marriage.