HTTP CLIENT POST operation without extra headers

Hi, 

I'm trying to submit a POST request with no body to a remote API. The HTTP CLIENT POST Operation with CP Base 1.7.0 but I'm getting weird errors back from my application regarding chunking or content-length headers missing..

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN""http://www.w3.org/TR/html4/strict.dtd">
<HTML><HEAD><TITLE>Length Required</TITLE>
<META HTTP-EQUIV="Content-Type" Content="text/html; charset=us-ascii"></HEAD>
<BODY><h2>Length Required</h2>
<hr><p>HTTP Error 411. The request must be chunked or have a content length.</p>
</BODY></HTML>

Using wireshark it seems OO is automagically adding  an Accept-Encoding:gzip, deflate header which appears to be generating the error. I have removed all extra options from the HTTP CLIENT POST operation except headers, url and method but there is no change.

I am able to successfully submit the POST request manually via POSTMAN without errors so I know the query works when not sent by OO.

Can anyone help with a solution please?

Thanks, 

Andrew