Is partial fairness acceptable?

In USA v Barnette [2004] UKHL 37 (22 July 2004) the House of Lords considered the problem of whether a judgment from a foreign court should be enforced in the UK although that foreign judgment may have arisen from proceedings that were unfair to the party opposing enforcement. As it turned out, the HL decided that the foreign court proceedings did not involve unfairness, so consideration of the problem was obiter. However, of interest is the question of whether degrees of unfairness may be tolerated. Parts of Barnette refer to the need for a "flagrant" or "gross" denial of fairness, and the need for "an extreme degree" of unfairness.
It is suggested that a distinction exists between degrees of risk of unfairness, which is a proper consideration, and degrees of unfairness, which is a fallacy. Dicta relied on in Barnette refer to the threshold that needs to be met before the court will act to prevent a breach, in other words, how sure the court needs to be that a breach of fair trial rights had occurred. Some rights are subject to qualification, and in relation to those it may be correct to refer to a gross denial of them, but the right to a fair trial is recognised as fundamental, primary and absolute. References to flagrant breaches or gross breaches of the right to a fair trial should be read as meaning breaches which are clearly demonstrated and not merely speculative.