adder - 8:17 am on Apr 25, 2012 (gmt 0)
Thanks everyone for the input.
Providing additional material to make the reviews look unique is not possible because we're talking about several large sites with a huge amount of reviews.
The reviews are there for the benefit of the visitor. Adding content for Google's sake wasn't the main objective. I have already established that I've been hit by Panda, so it's not really a question whether to make Google de-index the reviews or leave them be. It's the question of what's the best way of de-indexing them?
So, @Robert Charlton, you reckon I could put noindex on each review page and then just wait for Google to de-index them?
if you drop robots.txt it shouldn't be necessary
Sorry, didn't quite get this bit...