My Occam’s Razor doesn’t compute trying to merge two totally different appearances into one person.
Nor me. But it is still more likely than two different people being seen with a child and reported to Scotland Yard. And Scotland Yard never mentioning the second report.
This was a quick exchange. People passing in the street at night walking in different directions. And no reason for the Smiths's to pay any particular notice. I have read elsewhere that a father carrying his young child is a pretty common occurrence in Portugal.