This is a really awkward space! What about trying to build a unit into the corner which seems to be dead space. This could house the television and other bits like dvr,amp etc. The unit could then extend out towards the door in length and in height either up to the start of the window or up to the start of the blinds. I would suggest drawers for toy storage and books above. In this way you leave the windows clear for light plus it looks like you have a pull down screen so the tv would be out of the way of that. This arrangement would also hide all those wires and cables! Ikea have some good examples of storage which you could adapt or copy, such as Besta which illustrates the extended toy storage. http://www.ikea.com/gb/en/catalog/products/S39927155/

Deep gray and all the other accents in silvery old wood and cream. This will add drama, allow the other elements to bring ion light and set off the concrete wall as a true feature. If you want light instead of drama, then go for a very pale beige stone. It will echo stone colours in both the concrete and rocks...

Yes, the brown wall is actually deep purple (aubergine). The carpet is more dark grey than brown. It is not a commercial place, but a large family home, and all the extra chairs are around because we were about to have 22 in for dinner, so the table was fully extended to it's 6metres! (The lounge is totally separate to this room, this is family space, so has the old sofas for sacking out on) But I really appreciate all suggestions and comments as it would be good to pull it together, even when entertaining so many. Cheers!

How about something like the below up and down wall lights in a black/dark charcoal. Up and down beams can be adjusted and when lit at night, they will show off beautifully the linear cladding.