I received an email in Late May.offering 40KG luggage allowance.After I booked ticket for a friend and myself purely because of avaiability, I noticed Luggage Allowance to be 30 KG on the way out and 40KG on return journey. I took this up with Emirates through Twitter, Text below is part of reply received from Emirates through Twitter.

*****Additional 10kg allowance applies only to Economy Saver fares. Special, Flex and Flex+ fares are excluded.*****

After not getting anywhere with Emirates I refred this matter to Advertising Standards Agency. Throughout the Emirates email its not mentioned that offer only applies to one specific type of fare and excludes evrything else. ASA requested screen shots of email and my booking,which I forwarded, after few days they requested the original email, which I forwarded aswell and now waiting for their response.