The template you are using is quite heavily customised, so a LOT of core zencart behaviour has been modified.
Because of these customisations, many questions you ask on this forum may not give you the answer you need, because people answer stuff largely based on CORE behaviour.
FOR EXAMPLE... Your question:
The main sliding banner at the top of the home page i am thinking of changing this to the logo of the brands which i am now stocking instead of the pictures of children. Then the pink box next to it with the free postage deal in it removing this completely and just have the sliding bar going over that area aswell.
CAN actually be resolved by putting the following declarations at the bottom of your stylesheet.css file
Code:
#right_wrapper {visibility:hidden; height:0px}
#left_wrapper {width: 888px;}
But there is no core "left_wrapper" or "right_wrapper" DIV in standard zencart.
Your designers have structured this themselves.
While this is perfectly permissible, it does mean that people helping you may need to spend time learning your site structure first.