Wont the customer mind you walking on her sofa. Paul
You always get one dont you :

Paul, to walk on someones sofa is utter madness, what I was sugesting was remove base and back cushions, lay them out on the carpet then wand them as if you were wanding a carpet doing both sides, once cushions are cleaned put them in front of a drier, then wand the suite frame, back sides and front, then finish off details with hand tool, arms, fringe, sides of cushions etc.
Your quite welcome to walk on clients suites Paul, just dont expect a repeat client!!

don