Having stupidly filled up my wife's diesel Yeti with a full tank of petrol and realising it only when I went to pay and accepted the offer from the service station to get it trailed away for a tank drain by their "local garage" the saga began. After about 10 miles on a tank of clean fuel, a buzzing noise from the engine compartment. It stopped after stopping the engine and restarting but reappeared after another few miles . During lock down we rarely drove more than 10 miles so lived with the noise. Took it to our village garage with the engine running after driving some distance and tracked the noise to the fuel pressure regulator / electric pump on the bulk head. Replaced unit problem went away. Drove long distance noise back with vengeance! Took to main dealer who identified that the outlet and drain return pipes on the tank fuel pump unit had been cross connected. Problem solved. Cant understand how performance was ok with crossed connections! I had Googled the symptoms at the start but did not come up with the answer - perhaps this post will help.