>> the more I feel it should be a web app which is not really my bag I can do basic stuff but I would need to ensure this app is only available to a select group of people

The smart money has turned completely away from web apps for devices. Amazon, Ebay etc made their fortunes on the web but they offer native apps rather than web apps for devices. If your app is more complicated than placing an Ebay bid, you'll soon see why. Consider the effects of a timeout on a web app as well as Viv's point about cool features that Apple and Android users expect, not all of which are available in a browser.

IMHO the vendor market has completely lost its way. An Apple/Android version of something like dBase with lazy data sync ought to be easily delivered rather than a Rube Goldberg concoction to mimic functionality that users could write for themselves in the DOS days.