Part one of the CPR Rules on the overriding objective states that active case management by the court includes "giving directions to ensure that the trial of a case proceeds quickly and efficiently".

To take two examples: the court can order at its own discretion the summary disposal of issues which do not need full investigation at trial; and secondly, it will not allow the movement of trial dates except in exceptional circumstances.

So you will need to plan ahead. When completing the allocation questionnaire, you will have to plan what sort of representation you envisage at trial and give an estimate of the length of trial.