We've had this a while and think it is the base for our Aquo TV, which we have not used because we fixed the TV to the wall instead. There are several screws and other potentially useful bits and pieces.
The base is quite heavy glass and measures 450mm x 275mm.
I'm hoping someone might find a use for some of these fittings at the very lease because I'm not sure I can bear the thought of just chucking this all in the bin!