I have been told by HMRC that the entries for VAT on imports from the EU should only be entered when a Postponed VAT Statement is issued.  

At the moment Sage does this 'magically' but it is not necessary correct for timing.

Please would you remove this new improvement or, at least, give the option to delete the Credit note that is generated automatically and amend the Supplier invoice VAT to zero. 

For your information I have set up a supplier called HMRC.  When I receive the Postposted VAT Statement I enter as a net value for goods, T30 Tax Code and a Tax value of the relevant amount.