Are padded walls  - where fabric is stretched between battens over padding - subject to the same restrictions as, say,

cushions or pillows? Does there need to be a liner between the padding and the fabric, if not fire resistant, or does this fall in the exempt category?

As a wall lining it would be subject to Building Regulations and Fire Regulations and depending on location and area to be covered would have to conform to certain requirements regarding flammability and surface spread of flame, so it's a moot point as to whether the furniture regulations apply or not.