Noise from Evoque LeftRear wheel well after parking

I have just bought a 2013 Pure Plus. Sometimes when I turn off ignition there is a humming noise coming from the left rear wheel well. It goes away after several minutes. What is this noise and does it signify a problem?

High pitched whine, yes it's normal, have yet to know what it is for certain!

Maybe related/ similar but we had an odd noise from our Sienna. Sounded like a small fish pump. Called the dealer who said it was an "Evaporation Leak Check" function.