Thanks for the heads up Tiggery.
I have just got off the phone from Virgin (yes they are open Good Friday) and reserved seats for 21st Oct/5th Nov.
The recorded message still says you can only book 180 days out but I hung on anyway and the nice lady at the other end confirmed you can now book 11 months out regardless of what the message says.
However she advised me that pre-booking only starts with ros 34 and higher for Economy - they wont book anything nearer the front of the plane.