Why do I have no VAT due on Sales

As an example of this, here’s a spreadsheet I created by doing “download calculations” on the VAT return preparation screen. I then imported the Purchase_Invoice_Items.csv from my most recent backup as a second worksheet in the same book (this was on Google Sheets rather than Excel but the principle is the same). I could then put a couple of formulas against each “PURCHASES” and “PURCHASES FROM OTHER EC MEMBER STATES (Products)” row:

The “net” formula is

=SUMIFS(Purchase_Invoice_Items!G:G, Purchase_Invoice_Items!$B:$B, "="&B110, Purchase_Invoice_Items!$D:$D, 5000)

i.e. sum all the entries in column G (the net) where the QFnnnn purchase reference matches this row and the nominal code is 5000. The formula for the VAT is the same but H:H instead of G:G (same row filters, but sum a different column), and the gross total (column J) is =H110+I110 etc. You can see some different examples in the screenshot, though the “vat” numbers are all 0 as these purchases were all zero rated food items: QF02780 is a multi-line purchase where only some of the lines are code 5000, QF02594 is a completely different code (so the SUMIFS give 0), and QF02599 is entirely 5000 (so the SUMIFS results match the purchase totals in columns E and F).

Your final sales VAT is then the sum of column I, divided by the sum of J, multiplied by the total of your retail sales.