On stands - one in the far corner behind the armchair, the other where the airer is, assuming your main viewing area would be the seats that sit against the long wall. 

The alternative is at the right hand end of the curved sofa/couch but you run the risk of the speaker stand being in the way there and getting knocked over. 

They need to be at ear height, turned very slightly inwards. 

(With Trueplay, the sound would also be optimised for their positioning and room size/orientation.)

Stands would allow for slight adjustment of placement to ensure you get it right - wall-mounting is far more permanent, and the best placement for the surrounds just isn’t that certain.  

 I appreciate it’s a bit late now, but Era100s would be fine in that space. Era300s really pack some punch and might feel a little large.]

Hi Rhonny

Thanks for replying so quickly.

My current seating position is the recliner / armchair, so appreciate not directly opposite the soundbar,  still does pack quite a punch in this position though.

 

As for era300 placement, if I put one behind the armchair it would effectively be right behind my head, i guess this wouldn’t really work for the system?  

i only took delivery of the set yesterday, and I think the 30 day return guarantee,  do you think I should return and get the 100’s 

 

Also, as mentioned is it better for the arc to be on the wall below the tv,  or is it fine just sitting on the sideboard 

The Arc placement is fine.  Wall or on a table, there’s no difference.