Should Oxford college fees go, the university may have to persuade the bigger players to share a few more pennies with the poorer ones. But one or two will be left out of the game altogether. Mansfield, for one, will be watching from the sidelines. When it became a full college of the university two years ago, it was told it could join only if it promised to stay out of the scheme by which richer colleges deign to help out those worse off.