the checks should be automatic on 1st and 2nd Reference
the check should also check Opening Balance Invoices in a Invoice is entered as it is currently possible to enter an Invoice Reference with the same reference as a Opening Balance Invoice
Sage 200 Web Portal Purchase Invoice and Credit forms feature automatic checks on the Reference fields.
You can find out more details about the Web portal here:
the checks should be automatic on 1st and 2nd Reference
the check should also check Opening Balance Invoices in a Invoice is entered as it is currently possible to enter an Invoice Reference with the same reference as a Opening Balance Invoice