I would like to thank everyone who replied to my request, and for all the info provided.
Currently I only have sporadic internet connection, otherwise I would reply personally to each of you. So apologies and thanks.
For various reasons I missed a lot of what was discussed during the summer, but would like to put in a very late halfpeneth (sp?) re the 'complete grammar' discussion. The perspective I've been using is that of linguistic change. I've been looking in a very amateurish way at the change from [I was] 'impressed by' to 'impressed with' partly via corpora searches. As I don't know how to date utterances in the BNC I found its data to offer just some evidence of the change.
Perhaps others have looked into this/similar questions. Or perhaps this could fit into a doc. Thesis.
Again, thanks to all who replied.