Sidebar, changing display of sub pages

I need a section in my site called (for example) ‘working abroad’. There is a main intro page and then sub-pages. Currently I have created pages for these items, not posts. They won’t be changing or need comments.

I actualy wanted to be able to create individual sidebars per page, so that I can match sidebar lengths to page lengths (I hate untidy pages). It seems that I can only do this if I use individual widget areas, is this right?

In each sidebar there is the automatic listing of sub-pages, which is handy, but they are in the wrong place; at the top of the sidebar above the widget I use to add sidebar items. There is no title above the links and I seem to be unable to place it where I want. Ideally it will go in the sidebar underneath one or two other items such as logo/search bar/text block /image. How can I take the sub-page listing and add it to the widget? I saw an earler post that suggested I could disable the automatic sub-page links and then add a custom menu, but I’m not sure how to get this to do what I want; I looked at creating a custom menu but my understanding is that a custom menu has to be attributed as ‘main nav’ or ‘footer’ (etc) which means I can only have 3 (or is it 4) custom menus for the whole site. If I have a secondary menu in the top bar, a main nav and footer nav, how do I create a custom one to use in sidebars, and ideally more than one version (for different site sections)?

Thanks