Thanks spunk
Yes - logged in correctly and have been using the store since I downloaded the early previews last year. It just stopped working on two machines after the KB3149135 update.
Funnily...

I am unable to update my desktop and LINX 7" tablet since the KB3149135 with anything - Windows update or programme updates from the store
I can't uninstall it - settings says click and then choose...

In fact the new one, Notepad 8, seems to have problems opening 'large' files that my old notepad opens happily.

My ModeS radio and Planeplotter software produces daily logs usually around 2Mb-3Mb...