righto so I think I’ve fixed it, roughly here’s how
Entered Container
./launcher enter db-container
Accessed Discourse DB
su -c 'psql discourse' postgres
Had a look at the values of the deleted category
SELECT * FROM site_settings where name = 'staff_category_id'
This returned ID: 4
Found the Category ID of newly created staff category
SELECT id FROM categories WHERE name = 'new staff channel'
This returned ID: 15, which I re-assigned to the staff_category_id
UPDATE site_settings
SET value='15'
WHERE id='4';
AND name='staff_category_id'