In message , at 14:39:20 on
Sun, 20 Mar 2011, Steve Firth remarked:

Fares, as presumably you are aware, change based upon demand and
availability.

Some do and some don't. The £202 rail fare you quoted for Edinburgh
doesn't. Nor does the £499 air fare I quoted. (Although the airfare will
eventually sell out, whereas the train fare won't).

Those are the base points; fares cheaper than that may have quotas,
restrictions etc. and what price you get, depends on demand. Picking one
day in isolation is unlikely to give a balanced view.
--
Roland Perry