I've just moved into my new house and have noticed the heating isnt to great.The problem being (I think) is I have old single rads being feed with 8mm microbore pipe.They are feed by a condensing boiler(1 year old)and they are all placed under windows.Would it make sence to replace all the old rads with new double rads and move them from under the windows(I'm having a wall knocked down in January so they can be placed on the adjacent wall).