i noticed yesterday that my bl went from 141 to 0 but today they have returned to 141. also since my bl have returned i have a further 2000 pages indexed by google. is this to do with the datacenters thing?
Probably not. Google is (still) posting its big Panda update. Many expect them to post a Penguin update too. You are probably in the Google ranking dance. Don't draw conclusions until it stabilizes.
Page Rank updates happen all the time and that's why back links can vary quite wildly so just wait until things settle down a little bit more and all will be okay. it's good that Google has indexed more of your website pages and hopefully it means more visitor traffic