Wowsers this is infuriating!!!
So I've downloaded SF Thunder and tried adding a widget this way. No joy.
Might have a clue with the issue though since when I try adding an MVC widget, I get an "Object reference not set to an instance of an object" - could that be the namespace issue I alluded to above?
i.e. can you change your solution / web app name / namespace and add widgets?
Twenty minutes in, nearly in tears already :'(
Right. Seeing as this is right at the start. I'm going to treat myself to setting up the new VS and try again from scratch.