At the cottage just over my shoulder is where they had been growing cannabis

https://youtu.be/e4iRuwjrb1E

This is what I've transcribed:

Well, last August when it was found that Neil and Yvette Hartley had...had been growing almost 90 cannabis plants, little did their neighbours know that in this quiet corner -- this quiet pretty little corner in the Kent countryside, at the cottage just over my shoulder is where they had been growing cannabis.

Is there "at" before "the cottage"?

If so, is "at the cottage just over my shoulder" the subject of the that-clause?