The LINQ .First() command throws an error if no data exists
I incorrectly assumed that this would return null or an empty record if no data was found, but instead it throws an exception!
Instead I should have used .FirstOrDefault() which returns a null value if no record was found.
tblKeyword keywordRow =
ageRanges.FirstOrDefault(a => a.Keyword == setWord)
as tblKeyword;
Which returns either a tblKeyword item or null.