Ah ok, I see what you mean. Because there is a duplicate use of .post I need to specify the styling of .post .post – makes sense.
I have added the example code you provided into he style sheet .css and it solves a lot of the problems. The posts now are displayed in a tidy manager. I added the line background: none; to remove the background too which means it is all working fine.
Thank you very much for your time, it is appreciated.