blog page features another page

Sorry, that’s a weird title for this query, but I can’t think of how else to describe the problem in a few words!

In more than a few words, then:
I have almost completed my first website design using WP. I’ve been using WP for blogging for years, but not as a CMS.

I have created several pages (Home, About, Testimonials etc), which appear in the horizontal navigation menu under the header, as planned. However, on trying to create a ‘Blog’ page, I have encountered a problem – ie: the Blog page automatically features the ‘About’ page as a ‘featured post’!

According to Codex instructions the Front Page (‘Home’ in my case) should be set as static, and the ‘Blog’ page as ‘Posts’. I’ve done this.

I have selected one-column with sidebar as the template for the Blog page. All other pages were created as default templates without sidebar. Dunno if that’s relevant, but thought I should mention it.

Would be much appreciative if someone could point out what I’ve done wrong with the ‘Blog’ page. Thanks!

Cheers
Ross