Cars and vans driving and parking on a pedestrianised st

I work in a store on The Rock in Bury town centre. There are vans and cars constantly driving up and down the pedestrianised street on a daily basis. This street is pedestrianised so that shoppers can walk up and down the street without the thought of getting hit by cars and vans. The vans are G4S, The Post Office (has a back door in a service yard), Security Express. The post office also parks there van on the street while delivering post. These vans go up and down the street, park, reverse and complete 3 point turns. We have work vans that drive up the street and park or just park on the street while completing works. All of these pass a sign that states no vehicles at any time. There are bollards to stop them coming up the street but they are always down. The reason that customers come to Bury is that it is a safe street to walk down as it should be pedestrianised. I have seen vans reversing while people are walking behind there vans. We are a busy street and we need to be prioritising shoppers not cars and vans. We are getting into the busier months with summer holidays etc. There will be more people and children on the street so there could be an accident waiting to happen. The vans aren't allowed on the New Rock so why are they allowed to drive on the the Older portion of The Rock. Customers of the banks also just park on the street.