The Patrick heir-or-imposter theme still intrigues me.
If it is just left as it is, it seems to me to be an example of poor writing and/or editing - a subject which was just introduced to take up some time, and wasted it.
However it might be a real sleeper, with many possibilities for development.
Fiderer - a good spot on what the heir/imposter said, and what it might mean.
But I wonder - is this sort of subtlety typical of Julian Fellowes? From DA it seems to me that he is a good writer, but not a particularly subtle one.
Even if he is - the immediate theme isn't whether or not Patrick really is the heir, it's whether he can persuade the relevant authorities that he is. And in that case, would any of the DA family remember how he describes Edith at first - especially as they wouldn't have had reason to take particular notice of him, before his claim of being the heir. And even if someone did report this - would a court have to believe that, in the absence of a recording?
While most of the family didn't believe Patrick to be genuine, Edith seems to have believed that he was, and perhaps Lord G wasn't entirely sure that he wasn't.
The lack of a final resolution of the theme allows rich possibilities of development if JF and/or the DA producers want to go further with it.