CPR 47.14 governs delay in requesting a detailed assessment hearing. It very much follows the approach in CPR 47.7 regarding delay in commencing detailed assessment proceedings outlined at 24.1.

A detailed assessment hearing must be requested within three months of the expiry of the period within which detailed assessment proceedings were commenced. If the receiving party does not do this, the paying party may make an application to compel the receiving party to do so.

If the receiving party does not file a request with the court by the time the application is heard, the court may order that some or all of the costs claimed will be disallowed unless a request is made within a further, specified period.

If the receiving party requests a hearing date outside the time allowed by the rules for doing so, but in the absence of any application by the paying party, the only sanction the court may apply is the disallowance of interest at a subsequent hearing (unless there has been misconduct (see section 25).

Extract from the Senior Courts Costs Office Guide 2018