$sql = "UPDATE tbl_users SET 'Forename' = ?, 'Surname' = ?, 'Password' = ?, 'Email' = ? WHERE 'Username' = ?";
$statement = $conn->prepare($sql);
$statement->bind_param("ssss",$dbforename,$dbsurname,$dbpassword,$dbemail,$user);
$statement->execute();
$statement->close();