Hi Andy,
It looks like your supplier exposes some functionality of its web site as a Web Service (by publishing its WSDL).
If this my guess is correct, then, basically, this means that you should treat your supplier as a kind of a library functions set (or API). I.e. you can get only what is returned by the relevant web service methods and can do (add, change, etc.) only what can be done via the relevant web service methods.
Considering the above, you will need to design your own application and consider what data and actions you will need and to map these data and actions to the web service methods provided by your supplier and their parameters.
The cost of this work obviously depends on what functionality you need from your application and its (application's ) design.
