Welcome to the Q&A Forum

Agreed. You need to look at individual pages and associate those with those keywords. It's not surprising you're getting "jack of all trades, master of none" type data back.

You can also enter all your keywords into a tool like Rank Tracker and have it pull data so you can see which page on your site ranks for which of those keywords.

Correct; on google.co.uk it came up on the first page.

I think you answered your own question - there's confusion for the search engine. Similar keywords can do that- even though you say it's clear to you what page is optimized there's some data to prove that the search engines aren't in agreement. (I have a lot of pages and run into the same issue.)

Have you run the competing pages through the Moz optimization tool to see what feedback it gives you? If you see each page is an "A" for the same term, there's some information you can work with to start reworking your content to "un" optimize the pages you don't want to rank.

I like this article Rand wrote that addresses how to correct this issue: http://www.seomoz.org/blog/wrong-page-ranking-in-the-results-6-common-causes-5-solutions