I am not sure whether XC▸ Advance tickets are available yet for beyond 28th February.
Advance tickets, as I understand them, were designed to help fill unused spaces on quieter trains. With service slashed back on Cross Country routes from Southampton and from the South West into / via Birmingham, will / has the quantity of such tickets, especially at the lower cost end of the scale, shrunk our of proportion to the volume of passengers wanting to use them? In other words, are there now far fewer cheap journeys available resulting, in effect, in a price rise that's not reflected in high fares of the sort the media love to highlight?