Ok, so I've now managed to check the install for both n900 and n810.
On the n810 it weirdly claims the install failed, but the install seems to have worked. Any suggestions on how I can determine the problem?

On the n900 the install seems fine, but I can't get the launcher to work anywhere other than the command line. I thought it was a case of having the X-osso-service setting in the witter.desktop and a line in the python app to set a context that matched. but it doesn't seem to work.

I'd like to get these issues fixed before progressing.