Welcome to the Q&A Forum

Thanks for your responses. We are talking over 3000 pages of duplicate content which we have no removed and replaced with actual relevant unique and engaging content. We completed all the content changes on the 6/06/2013. Im thinking to leave it for a while and see whether our rank improves within the next month or so. We may consider moving the site to another domain since its features lots of high quality content. Thoughts?

Just checking in on this - it seems the predictions have panned out - as I see the site now shows 2,170 pages indexed on the site search. Has this resolved for you as well?

I agree with DrPete.  You cant have the pages within the robot.txt otherwise Google will not crawl the pages and "see" the 301s to then update the index. Something else to consider is on the new pages, have them canonical to themselves.  We had a site that Google was caching old URLs that had 301 redirects that had been up for 2 years.  Google was finding the new pages and new titles and new content, but were referencing the old URLs.  We were seeing this in the SERPs and also in the GWT.  GWT was reporting duplicate content for titles and descriptions for sets of pages that were 301ed.  Adding the canonical to self helped get that cleaned up. Cheers.

ok, apols for assuming name - just took it from user name and products. Will have a think and reply if anything comes to mind. There are some gurus on here who will be to the rescue soon no doubt!