Rework your while(){} loop like this:

while ($aline = <names>) {
    chomp($aline);
    @fields = split(/,/,$aline);

    $surn = @fields[0];

    next unless $surn =~ m/^B/i; # Skip entries that don't start
                                 # with B or b.

    $given = @fields[1];
    $suburb = @fields[2];
    $pcode = @fields[3];
    
    print "<tr>";
    print "<td>$surn</td>";
    print "<td>$given</td>";
    print "<td>$suburb</td>";
    print "<td>$pcode</td>";
    print "</tr>\n";

}
[download]