I have just imported my board over from vbulletin 4.2.2, and all custom fields have imported correctly and showing in my profile settings.
The problem is that i cannot see anywhere in the control panel user menu, where i can edit them. The menu option for custom fields just isnt showing.
Screenshot attatched. Any help is appreciated.
You are likely missing that permission. You will need to login as a super admin to add permissions to your user (or you can make yourself a super admin).
The super admin is controlled by a comma-separated list of user IDs in library/config.php. By default, it only includes user ID 1, but you can add your user ID to it if you wish. Alternatively, you would login as a super admin who can managed admins and admin permissions.