I've never been convinced that it was Sheila's foot,but------------------if that IS nail varnish that I can now see,and if it matches that which is on her fingernails,then it's questionable. I've seen feet,skin etc of the young deceased and after a few hours of being in a mortuary,they take on an appearance of an older person,for obvious physiological/biological reasons.
There's every possibility that it now is the foot belonging to Sheila because the former MP must have got his source from somewhere and someone he knew.