Thanks for raising this question in our forum, @Scanserv,
At the moment, the connection to link QuickBooks to HMRC's CHIEF System for making Customs Declarations is currently unavailable. We're unable to tell when this feature will be available in our software, as our engineers are working internally with product updates and enhancements.
To be updated with the recent changes in QuickBooks Online United Kingdom, see these links:
In the meantime, you may visit the HMRC website for instructions. This publication has all the information on how you can get or submit the declaration: Customs declarations for goods you bring or receive into the UK or EU
For other questions about our program, please let me know in the comment below. I'll be right here to help you with QuickBooks related tasks. Have a good one!