CCM12660 - Opening and Working Enquiries: SA enquiry closed
When an enquiry into the SA return is closed the return becomes final on the date of closure. The window for opening an NTC enquiry automatically closes on the same date. For example if a SA enquiry regarding 2003/2004 was opened on 1 May 2005 but was only closed on 12 April 2006 the NTC enquiry will have remained open until 12 April 2006. If an NTC enquiry has not been opened by that date it will then be impossible to open a S19 enquiry. If, however, an NTC enquiry has already been opened you can continue to work it. The closure of a SA enquiry does not mean you have to close your NTC enquiry.
In some cases the closure of the SA enquiry means the window for opening an NTC enquiry has closed earlier than might have otherwise been expected. If an enquiry into an SA return is both opened and closed before 31 January (i.e. before the SA enquiry window would normally close), the return will have become final at that date. In these circumstances, the NTC enquiry window will also close on that date. But note that this does not mean that any open NTC enquiry will be closed down - the closing of the SA enquiry window affects only the end date by which you can open an NTC enquiry, it does not have any impact on an open enquiry.
If the taxpayer subsequently amends their SA return (within the time limit for doing so), both the SA and the NTC enquiry windows will be opened up again (see CCM12625) unless an enquiry into the NTC entitlement had already been opened and closed. This is because it is only possible to enquire into the entitlement once under S19. In this case, you will only be able to follow up any queries in respect of the NTC entitlement if you can make a discovery decision - see CCM Chapter 13 (CCM13000).