Thanks for the replies and confirming that it should work.
Berkshelf version is 5.2.0 (chef dk 1.0.3). Other knife commands e.g.
knife status work, so I think my knife.rb settings should work for the authentication part.
The chef server has been upgraded from 12.3 where the chef universe wasn't available to 12.6.
knife raw /universe currently returns a
404 - not found so it looks like there is a problem, I will carry on digging.