Recover partially saved responses

I had a survey where I had to deactivate it, make some structural changes, and then import the VV file with the response data.

The survey had two partially saved responses, seen in the table _saved_control

When imported the VV file, the partially saved responses were not included.

Thankfully out of 2000 responses, only two were partials. But if it had been a hundred (easy on a large survey), their
loss would have been much more problematic.

So, I wonder -- where are those partials saved? And is there a way to view them or access the data, and restore them (even if it means DBA or data entry work) to the survey again?

As an update, I have discovered that their responses were in the VV file, and that they are back in the response table.

But, the record of this has been deleted from the table _saved_control

I have imported the two missing records from a backup -- but:
(a) will this work for the respondent? and
(b) any thoughts about how this could averted in the future?