All, not sure if this is going to help but found a fix specifically for the Lenovo Yoga S1 on another forum so thought I would share.
It is a bit of a weird solution and an indictment on Lenovo but believe me it worked for me after lots of frustration. It turns out that Lenovo has bundled some rogue software which has a significant impact on wireless performance. In task manager look for a process called "Discovery.exe". End this process and voila, wireless works and is stable.
The offending software is Lenovo EMC Storage Connector. Remove this in Add/Remove programs.
Hope this helps, certainly should on the S1