Wow, I didn't expect quite such a scramble when I made the post!!
I was also told this last year - that they wouldn't accept bookings until after test w/e. But I know for a fact that some people booked long before this. For the past few years, I have emailed them my order, whereas some people fax theirs. I have a feeling that if you email them, they have an easy way of responding (refusing) the order if it is too early - if the order is faxed, they can't easily respond.
Also bear in mind that Termie has offered to go and have a chat with the ACO people after the current activity has eased off a bit - to try to get some answers before we start ordering.
Del