Have a WF action script that has a trigger type of all on the WF, on create, view, update and within the workflow state - it's after record submit (the reason is I need to see committed quantities at line level which only happens after it's saved), problem is the WF is triggering via UI however if I create the SO via CSV, it doesn't trigger even though I've got all contexts on both the WF and the state? any ideas?

In your CSV import, under the advanced options, is the checkbox for "Run Server SuiteScript and trigger WorkFlows" checked?

sorry should have said, that's already set hence not sure...

CSV imports in NetSuite operate in adifferent context than user-initiated actions and may not trigger workflows in the same way. This is true for workflows with event triggers that are set to “After Record Submit”. The system might not consider a CSV import as a record “submit” in the traditional sense. But you can Check that the ‘CSV’ context is enabled both at the workflow level and the action level. In the Workflow definition, under the ‘Trigger Events’ tab, make sure the ‘CSV’ context is selected. Also, check the same under ‘Contexts’ in the Workflow Action definition. Check the Execution Log on the record created by CSV to see if there’s any error when you are uploading the CSV.