You have indeed wasted that one. I said in an earlier answer that nothing had ever stood there. Now a little more info as time is moving on and I intend to reveal tonight!
So a final pair of clues. The phenomenon will not be there when SWMBO is using the bathroom, but is highly likely to be there when I am'!
Very well thankyou Dormouse, she has now had all her dressings removed and is doing her exercise regime 3 times daily, plus walking around a bit on an hourly basis. She is now confident to use the stairs on her own although I have asked her not to yet if I am out shopping etc. I'd say recovery is pretty much on track!!