They had an uncatchy chant: "Peabody: shame on you!" that they couldn't keep up for more than a minute at a time. There can't have been more than about 15 people involved, so I don't suppose their numbers would cause the Peabody Trust to quake in its boots, but at least they were media-savvy enough to inform the BBC of their grievances in advance so that their protest could appear on BBC London's local news. This, it duly did: https://www.bbc.co.uk/news/uk-england-london-68645037.
OK, so a 9% rent increase is steep, but Peabody wasn't applying it to social housing (where rents are linked to local income) and it still meant that the rent for a three-bedroom house in central London was going to come in at less than £1,400 per calendar month. Given that the median rent for a three-bedroom house in Colchester (according to https://www.home.co.uk/for_rent/colchester/current_rents?location=colchester) is £1,000 more than that, the Peabody tenants look to have quite a sweet deal.
It's not as if the Peabody Trust is a typical landlord, using rent as the means by which the wealthy tax the poor: they invest their profits on building new social homes that they can subsequently let at low rates to people in need of accommodation. Colchester is raising the rents on its social housing by 7.7% next year, so calling for a rent freeze on non-social housing is rather pushing it.
While I sympathise with those who are having to find another £111 a month in rent, I rather side with Peabody here. They're doing their best. The enemy is inflation, not a grasping, money-grabbing, callous landlord.