@Starwasterthanks for the reply. I'm sure I'm using the correct fuels for the command and control engines for instance hydrazine with the early thrusters, yet the engineer reports that the fuel is unused and the thruster is not receiving the monopropellant that it needs. I've attached a screenshot of my craft in the VAB with the aerobe despin module as an example. It can't even access it's own helium tank.
This issue is occurring in career mode. When I go into sandbox mode I have many more fuel type options for the RCS thrusters and the only one that the engineer report won't flag as unused is the monopropellant, all others, hydrazine, nitrogen etc are flagged as unused and I get the "engines not receiving propellant" warning.
Again thanks in advance for any help or advice.