If the Order combines child and spousal maintenance it may be possible for her to apply for an extension of the SM element. A lot depends on the precise wording of the order. If you can reproduce the relevant section precisely we will be able to advise more effectively.
If there is no bar then she could apply for an extension but the application would need to be before the end of the term. Nominal spousal maintenance, ie a reduction to say £1 a year, is a mechanism to keep the door open for a future claim if the conditions are right.