No, that's a bit wrong. the officers who reported it were from the Met. And the Met then reported it to the City of London police. But it was the City of London police that didn't hand the information onto the investigators or the pathologist or anyone else. So not the Met covering it up, more the city of london police.
http://www.guardian.co.uk/uk/2011/may/09/ian-tomlinson-evidence-held-back