Resolved; replaced problem row with this: "'" + $Row.$Prop + "'"
Also needed to modify these rows:
$Insert = $InsertValues -join '), ('
$InsertQuery = "INSERT INTO $DestTable ( $( $Properties -join ', ' ) ) VALUES ( $Insert )"
Invoke-Sqlcmd -ServerInstance $DestServer -Database $DestDatabase -Query $InsertQuery
To this:
$Insert = $InsertValues -join '), ('
$Cols = $Properties -join ', '
$InsertQuery = "INSERT INTO $DestTable ( $Cols ) VALUES ( $Insert )"
Invoke-Sqlcmd -ServerInstance $DestServer -Database $DestDatabase -Query $InsertQuery
This code runs correctly in the ISE & in the SQL JOB.
Thank you very much for posting back - it really helps everyone out, especially those who come across your post when searching on similar issues.
Sue