Oil leak found after having car at dealers
I recently had the EGR valve replaced on my car (A4 B6 Tdi 130) and have since noticed an oil leak near to the end of the top turbo hose - I took the car back and the dealer has informed me that both turbo hoses need to be replaced - I have taken the engine cover off and cannot see any leaks from the pipes, but oil around the top left of the engine near the top turbo pipe. See attached pictures.
Is it possible that the dealer has caused this leak when replacing the EGR? - I never noticed any oil leaking before this work was done.
Any views would be appreciated