@jamie Hayes
It is normally pretty quick to whitelist an IP address.
https://docs.wordfence.com/en/WhitelistIP
I would check to make sure that their IP address was not blocked, then you can remove that IP address from being blocked and they should be able to access the site fine.
https://docs.wordfence.com/en/Blocked_IPs
Hello Jamie,
Seconding what Luke says here you should the Wordfence page “Blocked IPs” to make sure their IP is not listed there.
Whitelisting is supposed to override all rules though. If you check the list of blocked IPs while they are trying to access your site you should be able to see it getting blocked. If you do that, you can verify that you have indeed whitelisted the correct IP address.
Let me know how it goes!