Secret London... Website design

I have drawn up some initial designs for my webpage. I have focused it around the colour code that I have used for the different categories. My main issue is trying to make it as easy to navigate as possible, as their is a lot of information, and should probably also include a discussion forum.

 I have focused on doing some designs for each of the button pages, the home page and the sign in page. I think that their should be a sign in page before being allowed to enter the site to keep the exclusivity of the group.

 The design that I have decided to take further is the one that uses the London tube imagery. I like this as it keeps that navigation relatively simple, yet the visuals are interesting, with the colour change and tube line outlining the sub categories.

 Homepage.