Meridian Unplugged - Powered by MrTechGuy.co.uk Forums Discussion Meridian - Systems DSP5000 v DSP5500 differences

You should place your speakers on the long side of the room, not the short one. Doing so, you can place the speakers away from the corners and the wall to avoid to early reflections.

The sound influence of the distance to the back wall you can minimize with the M speaker built in sound correction.That's easy to enable and help with "corner" and "wall" placement.

I would make here the priority on the placement of the speakers.
I would go for a listen to find out which speakers you prefer. It depend on your musical taste and the loudness of your hearing.