Banns called at St Mary Whitechapel in October 1829 for an intended marriage of John Doyle, Bachelor, and Sarah Porter Morris, Widow. Could that be her? Not sure that the marriage actually happened though
Maybe she wasn't actually baptized with a middle name Potter, and there is some other explanation for using it? If the name Basted is some kind of variation of Bastard, which seems quite possible, there is a baptism of a Sarah Bastard 17 August 1787 at St Mary Whitechapel, parents William + Sarah. Living Rosemary Lane. Followed in 1790 by a Samuel John Bastard, bap 1 August 1790 at the same church. Living White's Yard. After that, have been able to find nothing of them, and again, no luck so far with a marriage for William + Sarah.
John