Buddypress / theme knocks out my navigation structure

Initially I was using the graphene theme but decided to change to Buddypress, hence I installed the randy candy theme. However, since, all of my submenus have disappeared. I also had a primary and secondary menu in the graphene theme, whereas now, I only have the option for one menu – this I can cope with, though preferred the graphene set up.
Is it just that the randy candy theme or buddypress do not support submenus?

Also…the pages that are in the menu seem fairly random, there are lots of pages missed out.
http://www.meetinbradford.org

FYI: Installing the Buddypress plugin doesn’t seem to be the problem as the menus remain in tact whilst the graphene theme is operational. However, WP advises me to change the theme to enable the Buddypress features BUT when I change it, and I have tried it with several themes now, my whole menu navigation screws up – the menus do not display as they are structured within the Menu screen of the control panel at all, they are in alphabetical order BUT some sub/child-pages have promoted themselves and others just haven’t turned up.

I also had some embedded url’s as links, so that by clicking on a sub-menu/child page/drop down menu, you were diverted to an external url in a new page. These have disappeared on the site.

I am now using the Buddypress default template and though some drop-down menus appear, others don’t.

Various parts of the Buddypress package aren’t available either. Key areas / menus of Buddypress are meant to be Activity, Forums, Groups, Members, Register & Activate. However, it appears that only Activity and Members has appeared.

Also, I created a page for Italian people, and titled it Welcome/Benvenito(a) within the page and then customised the name in the Menu area of the control panel, but this seems to have gone too as the title of the page in the menu is Welcome / Benvenito(a). But also, this page is actually a nested page 3 tiers down in my menu structure, so really shouldn’t be there at all. e.g. Groups> Language/Nationality> EU> Italian should be the path. It’s also worth noting that none of the aforementioned pages are visible at all.

Having spent basically all day searching the Internet, I am also confused with the terminology. Am I right in saying that all the following are different ways of explaining exactly the same thing. (Sub menu, child page, nested page, drop-down menu).

Within the Menu area of the Control Panel, everything remains exactly as it was before, apart from, as mentioned before, that there is only one menu, whereas before I had a primary and secondary.

NB: I have disabled all plugins, so its not a plugin conflict.
I would really appreciate any help, thanks so much.