Right. I'd assumed that Adobe had axed the upgrade path from CS5 to CS6 amongst all the CC kerfuffle a few weeks back.
 
In the UK, the major online retailers (i.e. Amazon, Wex et al) et al removed the upgrade packages from sale pronto after Adobe's announcement, and I suspect at Adobe's behest.
 
And searching for CS6 on the Adobe website, even trying to find the software at full price just kept taking me to the Sign Up pages for CC.
 
But having a look on Thom Hogan's (Google him) site this morning, he provided a link that takes you directly to the Buy page on the Adobe UK website. And then if you click "Buy" but change the "I want to buy" bit from "Full" to "Upgrade", you can apparently get the upgrade for 188GBP. I'm not sure what version of PS you need to qualify for the upgrade. And I'm not sure how much longer it will be available.
 
Thom Hogan provides a US linky too.

If this is mentioned elsewhere on MSG, then my apologies but I haven't seen it. And I post it because others may have assumed the same thing as I did.

ETA - Just had a look - the only upgrades offered are from Photoshop CS5 or the Acrobat X Suite, I think.