We would definitely recommend Paramount - they were a huge help in selling our flat. They got us an impressive amount of viewings in a short space of time.
Both David and Lionel were really helpful and supportive throughout the process - e.g. discussing at the start the various options we had, and what tactics we should use to give ourselved the best chance of finding a buyer. Then there were various complications because we had to also extend our lease, and they helped us through that.
Whenever we left phone messages/emails, they contacted us quickly - something which many estate agents are not great at doing. So in summary, highly recommended, they give you a very good service.