Hi Jillaine, my procedure for this type of question (Wylley/Marshall/Bruce??? ancestry), would be as follows:
1. Research the question through internet searches, with the keywords being the names of both husband and wife, trying variant spellings, perhaps adding a keyword for alleged places of origin or residence. This type of search will almost always come up with (1) any mention of the relevant family by Douglas Richardson; (2) any discussion of the relevant family on the gen-medieval forum; (3) any other legitimate research on the family that has been independently on the internet; (4) any mention of the family in old English county histories and books like Burke's; and of course (5) the usual array of useless unsourced websites that copy from each other. Assuming (as in the case of Agnes Wylley and her alleged ancestor Matilda Bruce) that only internet garbage comes up, my procedure would be:
2. Add a "disputed parents" paragraph, with embedded links to the alleged parents, to the profiles of both Agnes Marshall and Matilda (Bruce) Marshall. For Matilda (Bruce) Marshall, I would also add an "uncertain existence" profile, because it is quite possible that this person is pure fiction.
3. Post a message on the profiles of Agnes Wylley and Matilda (Bruce) Marshall, politely alerting the managers and trusted list that I intend to detach the parents if there isn't any forthcoming evidence. At this point, a profile manager may reply and say, "please go ahead and detach -- I don't know how those imaginary parents got there."
4. Start a G2G thread announcing my intention to detach if no evidence is forthcoming, and ask if anyone has information on this family and the connections in question.
5. Wait a week or so. If no useful information comes up, then:
6. Detach the parents, and remove the relevant immigrant (in this case, Denison) from the "questionable gateway ancestor" category.