Just checked mine and it's blank:
Key: ################################################################
Application Url:
Key type: Basic / Not-for-profit
Created date: 04/23/2015
Expiration date: None
Key Status: Enabled
It doesn't let me leave the field "Application name" blank. It's a required field.
Doesn't work for me. I obtained a Bing key and followed the instructions (and cleared the browser cache and restarted Firefox) but nothing has changed. Still can't see the original OS map.
There might be a workaround if you use pocket queries: Download the gpx-file -> convert into KML (for example by using gpsvisualizer.com) -> import into "My places" on bing maps. Worked for me. Didn't need any app key's or similar. You might need to sign up to bing.