stewboy

you are NOT screwed!

M3's are quite small. One time I was living in a VERY crowded space and fit plenty of speakers in. Just purchase a pair of stands and place the M3's NEXT to the TV, and pull the TV out from the wall a little. Aim the M3's with no toe-in. I have done it and it sounded surprisingly well, even at decent volumes.

Try as best as you can to space them out without crowding the piano. If you can move the piano AWAY from the TV at all, even a foot or two, that's a good improvement.

good luck!
show us pics when it's done!