So with some pointers from Emil at Flic support, HUB works if we adopt Authorization: Basic base64. I would comment that iphone/iPad and FLIC combination seem to work either way.
It was not obvious to me initially how to do this in the FLIC app ... so for anyone else wrestling with this ...
in FLIC app under your chose Hub, select the Internet Request"Hub Action"
add your URL which for me was http://192.168.1.nnn:80/api/sceneControl?id=nnn&action=start to run a scene on my home automation box (Fibaro HC2).
stick with GET http method (in my use case)
under the HTTP headers (Optional), set up basic authentication i.e. type "Authorization" in the Key field of the app
encode your "user:password" string using base64 (I used base64encode.org for online base64 encoding)
Prefix the encoded string with "Basic " including a trailing space
"Basic YWRtaW46YWRtaW4NCg==" is encoded "admin:admin" as an example. Key or paste all of this into the Value field in the FLIC app
Press the INSERT button on the right hand side below the key/value fields. You should then see this header line with a delete symbol (red circle white bar).
Press DONE to ensure all saved away
It should work now - check your user:password encoding as first trouble shooting and/or check you HTTP verb - GET, POST depending on your target system protocols.
Hope that helps someone else get there quicker than me.
