I did everything right even to the point of getting my clients to send their stuff in early (rather than the usual last minute) just in case and guess what... doesnt work. Software provider says its a 'known problem' (whatever the problem is) and to ring HMRC VAT.
I'm not bothering - havent been able to get through for weeks now.
So I've submitted the usual way. Clients will prob receive a letter so I've warned them.