doco makes reference to OAuthLogin.GetAuthorizationCode...where is this class?

Have you got the access token? Hamishjam 

I have not used the class that was uploaded by John_Dinning  so I cannot comment on whether it works or not but I have built my own class to get the access token

maybe that was why the class was removed from the online sample but like I said I have not tried using it..

If you have the access token then just create a SimpleOAuthKeyService and assign the values from the token to it and you should be able to run the following.  

let me know how you get on. If I have time I'll build a test harness and upload it to github for others that are stuck here...seriously considering leaving the .NET SDK and just using RestSharp/HttpClient to access the API

  var keystore = new SimpleOAuthKeyService();
                keystore.OAuthResponse = new OAuthTokens
                {
                    AccessToken = myobTokens.AccessToken,
                    ExpiresIn = int.Parse(myobTokens.ExpiresIn),
                    ReceivedTime = myobTokens.TokenTime,
                    RefreshToken = myobTokens.RefreshToken,
                    Scope = myobTokens.Scope,
                    TokenType = myobTokens.TokenType
                };



                // Get Company Files
                var cfService = new CompanyFileService(configuration, null, keystore);
                var companies = cfService.GetRange();

                foreach (var company in companies)
                {
                    System.Console.WriteLine(company.Name);
                    Debug.WriteLine(company.Name);
                }