Can you give room dimensions please.

The room is about 8m long and about 3.5m wide. Tried to upload a picture but it won’t let me so put it here

Mod edit: removed link and added image to post

I don’t like clicking on links, so haven’t looked at the picture…  How far apart are the chimney breasts?

I’ve embedded the image and removed the link 

The chimney breasts are the correct width from the look of the picture but it would depend upon the position of the seating. Is the only seating for the TV?  Also, if there is a possibility of a sound bar for the TV in the near future?  If the answer to those two questions is no and yes respectively, then you may want to position with side of the seating opposite the TV. ( It might look slightly weird mounted on the wall under the TV...

Only seating is for the TV and I may get a sound bar at some point.

So better to place on wall opposite the TV

In my opinion, yes.