Checkout Extension Blocks - Dynamic Line Item Message

Hi there

I’m trying to create a checkout extension block which will show a dynamic message for clearance items only, to state that they have a 14 day return policy. But I can’t get it working. I’ve tried triggering it by metafield and by tag but can’t get it to work.

I already have a dynamic customer support details showing for UK customers, and have added the ability to edit line items.

I currently also have Rebuy doing checkout extension upsell offers.

Is there a limit on how many items you can edit at checkout?