Since the app in the windows store still reads 'in-app purchases' I thought I'd go straight to the sketchbook.com website to download for my surface pro - the agreement that I'm expected to accept is 13,861 words long and includes phrases such as "Licensee acknowledges and agrees that Licensee ... may provide, and Autodesk and its Resellers ... may obtain, certain information and data with respect to Licensee (including, without limitation, personal information) " Hmmm...... :o
I used to work for Autodesk; I've never known them to do this before (give out a full version of their software for free). Nice!
The full version is now free....
Already had the free version. Set up an account for the fully featured version with extra pens, brushes, layers etc. Just done it. Thanks OP