custom validation rule(s)

I'm getting close to my setup working as I want but came across a problem this evening with the name of prospective club member.
When adding someone to the database (or updating their details) I have a set of validation rules like so...

PHP Code:

            'family_name'      => 'required|max_length[30]|alpha_numeric_space|min_length[3]', 


However this person's name contained an apostrophe, think "Scarlett O'hara", well you get the idea.
A look at the documentation and I thought it was a decent enough reason to create a custom validation rule. So created a file "app/Config/ClubRules.php"

PHP Code:

<?php
namespace CodeIgniter\Config;

class ClubRules { 


Then in Config\Validation.php added

PHP Code:

use CodeIgniter\Config\ClubRules; 


And updated the $ruleSets array with

PHP Code:

ClubRules::class, 


I.e., pretty much letter for letter as the documentation describes. However I get "Class 'CodeIgniter\Config\ClubRules' not found" which emanates from "CodeIgniter\Validation\Validation->loadRuleSets ()"

Not sure what I've done wrong