"56. We take him to mean that a judgment will not be erroneous in law simply because the structure of the rule is not visible on the surface of the decision so long as its constituent parts can be unearthed from the material beneath. On the other hand, the constituent parts will need to be more than a formal statement paying lip service to the sub-paragraphs of the rule; the judgment must demonstrate substantial compliance. As in Balfour Beatty itself, the controversy will usually be as to rule 30(6)(c) and (e) and it will not be enough to set out the terms of the rule if there cannot be found in the rest of the judgment material that demonstrates substantial compliance with the terms of the rule."