The terms 'psychoanalytic' and 'psychodynamic' are both used to describe psychotherapy based on psychoanalytic principles. The BPC uses them in the titles of its registrants to differentiate the way of working that they are registered as being able to do. (This doesn't mean they can't work in other ways - for example with couples or groups, or using CBT - just that the BPC has accredited the training that qualifies them for the modality they're registered under.)
It would be overly simplistic to say that the difference between psychodynamic and psychoanalytic work is based on frequency of sessions. But frequency is a way of indicating the factors involved in developing the depth of work in relation to unconscious dynamics, transference and countertransference. In addition, the dynamics relating to frequency link to the time in-between the sessions and how much the focus of the work is on the patient/therapist and how much this is affected by external realities and relationships. In less intense work, e.g., once weekly, the dynamics of the patient’s internal world are more often equally engaged with the external world, whereas with more intense work there is an increasing intensity of focus on the patient/therapist relationship in relation to the clinical work.