I'm an Australian citizen living in the UK on a Tier 5 Youth mobility visa (I expect the same assumption would apply to those on any Points Based Tier visa who is a citizen of a country not required to get a visa to enter Schengen for short stays).
I am assuming that if I leave the UK just before my UK visa expires, I should be able to holiday freely within the Schengen zone for a period <90 days even once my UK visa is no longer valid. Obviously any time spent travelling in the Schengen zone in the preceding 6 months would be deducted from the max possible 90 day stay.
I expect this is common behaviour for people to have a 'last hoorah' through the Continent on their way home after living in the UK for a couple of years.
Thanks for any assistance
James.