The 2016 dated annuals were published in July, and available from Amazon then, but it looks like High Street shops have finally decided to put them on the shelves now. WH Smith is currently doing a deal whereby if you buy one annual at full price you can have another for a pound. That works out at about the discount you'd get if you bought two annuals from online sellers.
I know many people are tempted to wait until after Christmas, hoping to get them all for a quid each but if we all did that annuals would quickly die out as it simply wouldn't be worth the bother for publishers and retailers to do them for such little return. Thankfully there do seem to be enough people who support the UK comics industry who are happy to pay a little more and get the books early.
I've illustrated this piece with a couple of panels from my strips in The Dandy Annual 2016. I'm starting work on pages for the 2017 dated Dandy Annual now, but I won't be previewing those for a good while yet.
If you have difficulty obtaining the annuals you could always get them directly from D.C. Thomson at their online shop: