“It was not for him to add some gloss; and the gloss he added was not merely wrong but quite inconsistent with Lord Collins' authoritative guidance in at least two respects. In the first place, a ‘substantial’ or ‘solid’ case, contrasted with a case which is ‘wholly unmeritorious’, is not a case requiring a 50% chance of success, and with all respect to Mostyn J's view Lord Collins said nothing to suggest it is.”