On the site I want to cut down on customer contact (eg, emailing to ask if XYZ surname is available) - so I definitely want some sort of search box.

I have all the surnames in a txt file (I think there are about 50,000 surnames). So it's pretty large. A while back I worked on a site with something very similar though this was for searching "town names".

The PHP code goes like this;

function haveSurname($surname) {
$got = false;
$fp = fopen('file.txt', 'rb');
while ($line = trim(fgets($fp))) {
if (strtolower($line) == strtolower(stripslashes($surname))) {
$got = true;
break;
}
}
fclose($fp);
return $got;
}

As you can probably tell, this searches thru a file and returns "true" (1) or "false" (0) depending upon whether the term searched for exists! Linking the above code to a simple input in a form;

< input id="search" type="text" name="surname" / >

and then echoing the result;

echo (haveSurname($_POST['surname']) == 1) ? "Found " . $_POST['surname'] : "Sorry, " . $_POST['surname'] . "not found.";

Will tell the person searching if their name exists in the database or not. Of course, if the surname doesn't exist I could offer a service where I spend time investigating their surname (obviously for suitable expenses), but I don't want to offer that right now as I want this site to consume as little of my time as is possible.