Many thanks for the responses.
Michael, the way in which I'd typically manage this would be create a smaller installable agent which did the bluetooth connectivity and sync'd the info to the web app/cloud. So you'd still need an installable but it would be to do that part. The mobile apps would have been an installable from the appstore so, they could include that connectivity within the native portion.
However I definitely hear the points being made on the app frequently being used without connectivity, and there's a very strong case there not to go the cloud based web app route. So I'll shelve that idea, and go look at ways in which I can help the existing development efforts underway.
Thanks again for the insights and views.
Wayne