Worth checking - what impact has there been in:
- VAT reporting in core transaction system(s)?
- Reporting in spreadsheets and other user-written systems?
Looking at complying with the VAT rate changes as profitably as possible
Further details below.
Pending receipt of a requested credit note, one option is for the customer to record a dummy credit note to reduce the amount claimable, and reduce the amount payable to the supplier. This can be reversed if the original invoice is found to be correct.
Likewise if a supplier notices that invoices were raised at 17.5% which should have been 15%, they should raise a credit note and notify their customer. Otherwise the full 17.5% should be accounted to HMRC as output tax.
Clearly it is in everyone's interests to avoid such problems. It's worth raising invoices right first time.