Well it's a good job I checked with ACSI!
As my books and card have still not arrived, I emailed ACSI to ask where they were only to be told that as there had been a problem with my 2016 payment and no direct debit authorisation had been received, it had been assumed that I wanted to cancel my membership.
This rang a bell. On return from our September holiday in France when we used our ACSI card every night that we were away, I found a letter awaiting me stating that due to some problem with their payment system, they had been unable to process my last payment so would I now make a payment?
I can remember doing this immediately but what a job I've had finding the payment. It wasn't on my credit card statement nor had I made a PayPal payment. I had in fact made a one-off bank transfer on 01 October but my subscription had not been reinstated for 2017.
My suspicion is that when my previous credit card expired, I neglected to change the details on my ACSI account. As others might fall foul of this, I thought I'd best mention it.