Install smaller radiator

[Rooftile]

Hello, I'm new here and very much an amateur, but was hoping someone would be kind enough to offer their advice!

 

My sofa currently has to sit away from the wall as I have two radiators either side blocking it. I was thinking of installing smaller radiators to allow the sofa to go all the way back, but of course the current pipes would need to be moved outwards as well.

 

Is this easy enough to do or are there any other options? I've attached a picture which hopefully helps. It's the same on the others you side of the sofa too. 

 

Any advice would be greatly appreciated. Many thanks!