Fake clothing on Amazon.co.uk?

I've bought these Craghoppers Bear Grylls Survival Trousers from amazon. (see link http://www.amazon.co.uk/gp/product/B003TWOFKM/ref=oss_product ) These were sold directly by amazon and NOT by a 3rd party seller. I came across fake hiking jackets on Ebay which got me worried about my purchases and so I decided to contact amazon to make sure nothing they've sold me is fake. They reured me that everything that is from amazon (not 3rd party sellers) is 100% geniune. At the same time I contacted Craghoppers to double check. Unfortunately they said the only clothing they can gaurantee not to be fake are those sold on their own site and from no other. Now the problem is that these trousers have really poor stitching, there is no original mark on the craghoppers logo & it says 'made in China' (counterfeiting capital) . Do you think its fake despite being directly from amazon (they did come with labels and a lifetime warranty though)? if they are fake can i take legal action..I have the invoice..etc cheers