Please read the stickies at the top of this forum.
Namely: http://www.flyertalk.com/forum/briti...ad-sticky.html

Which then has a link to: http://www.flyertalk.com/forum/briti...l#post19761541

Also if you search this forum for "Istanbul Lounge" you will find the following as well as many more:
http://www.flyertalk.com/forum/briti...-istanbul.html
http://www.flyertalk.com/forum/briti...rmanently.html