Hi Glenn, please see screenshots below. Personally i feel that its the period ID i.e. FINAL that is different from usual VAT return period IDs, and the form type is FINAL..usual VAT returns have VAT100 as form type.
If these two can be implemented in QF then the user can put in the PERIOD START DATE and PERIOD END DATE.
(see previous screenshots on this thread as well).
So in reply to HMRC's reply to you, yes indeed - the dates for the open period can only be put in by the user. (its the FINAL period and FINAL form type that the user on QF can not enter).
These dates can be different for all users i.e. if you see this one below its actually going backwards i.e. 30th Sept - 1st Oct.
This is just my view, i don't know how it all works in the background to develop or structure it. ...