“52. We will approach the third Martland stage by performing, as Martland requires, a balancing exercise. In that balancing exercise, the need for litigation to be conducted efficiently and at proportionate cost and for directions to be complied with must be given particular weight. However, it remains a balancing exercise which invites, among other considerations, a consideration of the nature of the reasons for the breach of direction and the results that would follow if the appeal is, or is not, reinstated”