Mr Streeting did not insult fellow Labour parliamentary candidate Diane Abbott during an appearance on the BBC.
Data revealing a majority backing an elected head of state is taken from 2019, showing attitudes under a different Labour leader and monarch.
Ballots can be cast in person, with a postal vote or by a proxy.
Government figures suggest some delivery drivers are operating without valid work permits, but it is not clear how many.
Potential figure of 13.7 million migrants was estimated over a longer period than suggested.