To ensure that you have precisely the Songs you need ahead of your journey it would be better to synchronise over a wired connection - simply switch match off, synchronise, switch match on - match will not remove the Songs and they will be there for listening on the Tube.
From your description is sounds like iTunes Match is completing a series of updates over the air to your iPhone which are simply not completing in a timely fashion. It should be possible to update whilst in WiFi range ahead of your journey - allowing update over mobile comms will inevitably be a slow experience.
So what you're saying is that Match fundamentally doesn't work? What's the point in me paying for such a service if I have to disable it to acheive a job that it should already be doing.
Generally Match is fine, it is just this really annoying & illogical behaviour of the tracks physically disappearing from my iPhone instantly after they have downloaded (which proves that the connection I am using is sufficient for the purpose whether it be wifi or 3G).
Why does it takes hours for them to reappear when they shouldn't be disappearing in the first place?
I will send some feedback to Apple in the vein hope that they can fix the bug.
Thanks for taking the time to respond