THE CACHE IS NOT AT THE POSTED COORDINATES
To locate the bonus cache you will have to complete the A Walk around Queen's Quarter Adventure Lab Cache.
You need to have or download an Adventure Lab app to explore and complete the adventure. The app is available for IOS and Android here.
To access the adventure click on the link or scan the QR code below:
A Walk around Queen's Quarter Lab
At each stage an image will be revealed in your journal including information to find the cache location.
The cache is located at: N54 35.CAD w005 56.E(Ax2)B
You can validate your puzzle solution with certitude.