Xamarin Forms and DropBox - get " Bad HTTP Content-Type" error when downloading file

Hi all,

I was sure I'd posted this question to the forums already but my profile does not show any questions having been posted so I'm trying again.

Ok, so I have an existing Winsdows10 UWP app called "PassPort" which uses v2 of the standard DropBox API to upload and download data files without issue. Now I want to get this app working on my Android phone (Nokia 8 running Android 8.1) so I created a XF project, copied my download/upload code over to the main project and added Xamarin.Dropbox API from NuGet. I can create a valid Dropbox session, get basic stuff like user details etc but when I try to download a file I get this error:

Error in call to API function "files/download": Bad HTTP "Content-Type" header: "application/x-www-form-urlencoded". Expecting one of "text/plain", "text/plain; charset=utf-8", "application/octet-stream", "application/octet-stream; charset=utf-8".

Now I cannot see anywhere in the Xamarin.Dropbox API that allows me to specify a content-type for the header so I am really stuck!

Here is the code I'm using to download the file - this works perfectly every time with the standard Dropbox API.

    public static async Task<string> DownloadFile(string filePath, string fileName)
    {
        string output = null;

        try
        {
            if (dbxClient == null)
                dbxClient = new DropboxClient(accessToken);

            if (dbxClient != null)
            {
                var downloadResponse = await dbxClient.Files.DownloadAsync(filePath + fileName);
                var output = await downloadResponse.GetContentAsStringAsync();
            }
            else
                throw new Exception("DownloadFile: DropBox client not authenticated");

        }
        catch (Exception ex)
        {
            Exception = ex;
            output = ex.Message;
        }

        return output;
    }

Now I'll admit this is my first Xamarin Forms project so perhaps I'm doing something wrong but the app runs perfectly Ok on the "Android_accelerated_c86_Oreo" 8.1 emulator until I try to run the above code...so does anyone know how I can resolve this?

Please don't tell me to post over on the official Dropbox forums - I did that and they replied that as it's a Xamarin specific version of the Dropbox API, I would need to ask over here on the Xamarin forums.