HiWe need more details, you say it started after a service. Have you tried the obvious things such as checking it is fitted correctly/securely or that there's not a stone caught between the disc and disc guard?
Does it make a noise in a straight line, when cornering, over bumps, braking etc. What is the noise like? whiring, scraping,knocking? How long after the service did it start, was it soon enough to take back to whoever serviced it?