groundloop, my apologies... I was not clear.
Until December 2007, Virgin XC services used to serve OXF, hence my referral to them. But you are correct, Virgin XC services are now part of the CrossCountry Trains franchise (a merger of Central Trains and Virgin XC).
The fact that the service levels didn't change when the franchise changed, clearly shows that Virgin XC was getting better before they became XC Trains.
Again, my bad.
S.