I pay my VAT on Feb, May, Aug and Nov. When VAT Moss came in, it started on January 1, so that gets paid on March, June, Sep and Dec. If you don't know about VAT Moss and you sell services online to EC countries, you need to find out about it.
This means that I have to calculate my VAT six times per year, when it used to be three. And the calculation is a lot more complicated, because when I pay VAT, I have to calculate only the sales to the UK for Feb to May, but when I pay VAT Moss, I have to calculate sales to EU countires (excluding the UK) for Jan to March. So it's annoying that now I have to work out VAT twice as often, and it's doubly annoying that they are out of phase by one month, which makes it even more complicated.
So I had a brain wave. And I called HMRC on 0300 200 3700.
After a very long time on hold (I didn't time it, maybe half an hour?) I got to talk to a person, and she was very helpful. I can't change the dates when I do VAT Moss, but I can change the dates of VAT. You log into the HMRC VAT site as usual, go to "Change registration details", then "VAT return frequency", and then you choose "march-june-sep-dec". Simples!
So, after a careful conversation with my book-keeper, I'm going to do that. There will be one or two more complicated returns to do, but in March of 2016, I should be all synchronised!