So it does look like the solution works great. (And an impressive engineering team, knocking down problems one-at-a-time.)
But what is the problem again?
And I'm not trying to disparage this effort - only the marketing explanations look to me naive or dishonest.
To be more precise, this claim of better lift to orbit:
Carrying quite a bit of extra hardware so that you can fly obliquely through the atmosphere to save a small fraction of the oxidizer weight, then claiming that overcoming the thick atmosphere in this manner is an achievement, just does not quite add up.
As to London-to-Sydney: what will be the idea for redundancy here? One glitch in this pre-cooler and I imagine the consequences will be spectacular.
Again, not in the spirit of disparaging the actual science/engineering of this thing.