I’m afraid I did it manually. The new tax year in the UK started on April 6th – when I posted about Moneywiz, I was running both GNUCash and Moneywiz separately (i.e. putting data into both at once).
Come April 6th, all data just gets entered into Moneywiz (I always started a new GNUCash file for each new tax year).
Unfortunately that doesn’t help you much.
I assume you mean GNUCashtoQIF? If so, did you make sure it was saved as an XML file (GNUCash also has the option as saving to an SQL file) and made sure that compression was turned off? (from memory, it’s enabled by default).
Either way, hope you can get sorted!