Working with Seed BLE Shield and Adafruit Feather BLE
Although the nRF51822 supports Central (master) mode, the Adafruit Feather's firmware only support's Peripheral (slave) mode.


  The Bluefruit LE firmware from Adafruit is currently peripheral only,
  and doesn't run in Central mode, which would cause the module to
  behave similar to your mobile phone or BLE enabled laptop.
  
  At some point we might consider a new firmware image offering this,
  but since 98% of the uses cases for BLE involved running as a
  peripheral we've concentrated all of our development effort there for
  now.
  
  https://learn.adafruit.com/adafruit-feather-32u4-bluefruit-le/faq#faq-2


The HM-11 on your Seeed shield is capable of Central (master) mode though. This means your Uno will play the part that your Android phone was playing when you connected the Feather to the terminal app. 

To set your HM-11 to Central mode, run the following AT command. 

AT+ROLE1


Example code for the HM-11



Alternatively, you could burn the S120 Soft Device and your own custom firmware onto the Feather's nRF51822. You can find all the docs, tools, and Soft Device images on Nordic's website.