React-dropzone Upload to S3 from client returns 400 bad request - amazon-s3

Question

I am trying to implement this code example here to upload an image to an S3 bucket.
My server seems to return the pre-signed URL OK, but the PUT request that follows fails with a 400 error.
Here is the server-side pre-sign code:
var s3 = new aws.S3();
var params = {
Bucket: secrets.aws.bucket,
Key: body.filename,
ContentType: body.filetype,
ACL: 'public-read'
};
s3.getSignedUrl('putObject', params, function(err, data) {
if (err) {
console.log(err);
return err;
} else {
console.log('URL sent back to client ------------------------------------');
res.status(200).send(data);
}
});
And here is the upload action client-side:
export function uploadFile(data) {
var file = data[0];
return dispatch => {
dispatch(dropFileAccepted(data));
return makeUploadRequest('post', {filename: file.name, filetype: file.type}, '/signURLforS3')
.then(function (result) {
var signedUrl = result.data;
var options = {
headers: {
'Content-Type': file.type,
'x-amz-acl': 'public-read',
'x-amz-region': 'eu-central-1'
}
};
return axios.put(signedUrl, file, options);
})
.then(function (result) {
console.log(result);
})
.catch(function (err) {
console.log(err);
});
};
}
From the network request/response headers it looks like the content-type and CORS configuration on the bucket are correctly set, but I'm unsure whether there could be an issue with needing to set the region.
or do I need some additional settings on the bucket, like a bucket policy, or specify a Signature version ?
Request URL:https://XXXXXXXXXX.s3.amazonaws.com/brand.png?AWSAccessKeyId=AKXXXXXXXXXXXX&Content-Type=image%2Fpng&Expires=1460128516&Signature=%2BooCHlrwelBYC9fMYnu01PokgWM%3D&x-amz-acl=public-read
Request Method:PUT
Status Code:400 Bad Request
Remote Address:54.231.192.36:443
Response Headers
Access-Control-Allow-Methods:PUT, POST, GET, HEAD
Access-Control-Allow-Origin:*
Access-Control-Max-Age:3000
Connection:close
Content-Type:application/xml
Date:Fri, 08 Apr 2016 15:00:17 GMT
Server:AmazonS3
Transfer-Encoding:chunked
Vary:Origin, Access-Control-Request-Headers, Access-Control-Request-Method
x-amz-id-2:rXMCu6YD5mLrN3beBCs+kmXDGzhzrQHV2fTUTNooWXBQuPfLNOKDcArGQWRj+NLk+zo=
x-amz-region:eu-central-1
x-amz-request-id:FC181ED154
Request Headers
Accept:application/json, text/plain, */*
Accept-Encoding:gzip, deflate, sdch
Accept-Language:de-DE,de;q=0.8,en-US;q=0.6,en;q=0.4,fr-FR;q=0.2,fr;q=0.2
Connection:keep-alive
Content-Length:16819
Content-Type:image/png
Host:XXXXXXX.s3.amazonaws.com
Origin:http://localhost:3000
Referer:http://localhost:3000/admin/blog/create
User-Agent:Mozilla/5.0 (Macintosh; Intel Mac OS X 10_11_1) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/49.0.2623.110 Safari/537.36
x-amz-acl:public-read
x-amz-region:eu-central-1
Query String Params
AWSAccessKeyId:AKXXXXXXXX
Content-Type:image/png
Expires:1460128516
Signature:+ooCHlrwelBYu01PokgWM=
x-amz-acl:public-read
Thanks in advance for any pointers. I've been pulling my hair out over this...