Burkes Peerage: The info you are describing,should have included the
statement "as far as they know" .
On March 31st 1551 Parliament passed a bill ,annuling William Parrs 1st marriage
and making marriage to Elizabeth Brookes legal.
perhaps ,and i do not have any records to prove this,Robert could have been there
son.Find My Past only has records back to 1575 .
It is going to be difficult for you to prove anything.Remember this is 500 years ago.