I finally figured it out. MY LR tv uses a different mounting bracket from that 'grommet-style' as is in the bedroom. Pictured below is the tv lying face down in front of the metal mounting bracket.
I reached underneath the bottom of the mounted tv to find the TWO spring-loaded clips, circled in yellow. Squeeze both clips - move the lever towards you (and the back of the tv).
Holding the clips, gently pull the bottom of the tv outward - towards you. The bottom of the tv will swing free. The tv can now be lifted up and off.
Like everything, it's dead easy when you know how!!