Mechanics moments in equilibrium

Youve not included the reaction at D? If thats S, balancing vertical would give
R+S = 20+5
and taking moments would giive a second equation to determine both R and S. The point about which you take moments does not influence the values of R and S. However taking moments about C would give S directly and then taking moments about D would the give R.

Youve not included the reaction at D? If thats S, balancing vertical would give
R+S = 20+5
and taking moments would giive a second equation to determine both R and S. The point about which you take moments does not influence the values of R and S. However taking moments about C would give S directly and then taking moments about D would the give R.

So I'm wrong then?
I did include D in my diagram.

You included D, but there is no corresponding vertical reaction force in your diagram, so an "S". There must be a verticall reaction force at D, otherwise the bar would rotate clockwise about C. Simply including a physical support is meaningless without the corresponding force acting on the bar.