Three arrests were made for the same offence last week.
Some 28 arrests have been made for obstructing the public highway, the force added.
Those arrested have been released under investigation.
A Met statement said: “This follows three arrests made last week for the same offence. A 55-year-old man, 45-year-old woman and a 49-year-old man were arrested for conspiracy to cause public nuisance on Monday, September 13.
“In total, Met officers have made 28 arrests for those obstructing the public highway.
“Those arrested have been released under investigation whilst the crime team fully investigate all lines of inquiry and pursue all possible offences committed given the amount of material they have seized.”