Hi mcjones,
Sorry if my answers had been deemed as too simple.
We always start with the basics because if we were to provide each and every question with a detailed answer, it is going to take up a lot of time and deprive others of the chance to get an answer. We would usually start with the information provided.
When the system is not working, ie stopped, some valves could get stuck and initial operation does not get it moving till it warms up, this could be due to bad fluid or a loose belt.
To find out if it is the pump that is weak, you need to get a pressure test done on the output of the pump.
If the pump pressure is within specs, you need to check the steering rack/box valve body. It could be internal pressure leakage which requires a rebuilt.
If you have not received the required informations, you are always welcomed to ask again.
We are not in direct contact with the car so we can only offer what we think should be done first. If more information comes in, we would then be able to diagnose it better.
Thank you.