Doh! Was stuck on this for 2 days, and figured it out 5 mins after I sent the email.
Forgot to do the correct init stuff:
self = super(currconvpyAppDelegate, self).init()
...
return self
which is the python equivalent of the objective-c:
if (self = [super init]) {
...
}
return self;
Sorry - at least hope this helps other people who get stuck. :)