https://www.slab.org.uk/guidance/granting-advice-and-assistance-timescales-for-notifying-us/
You must submit the online advice and assistance application within 14 days of commencing advice and assistance. (Additional information is not necessary, unless you need our approval, or need to give us information your client’s financial circumstances.) If you do not send us the form on time, your account is ineligible for payment. We can only accept late notification if we consider there is special reason.
Advice and Assistance application procedures
This page includes information on how to apply for non-templated increases in expenditure under civil A&A. It covers the information you should provide us with; case-related factors to address in your application; the process for reconsideration of refused increases; the process for urgently needed increases; whether authority for retrospective increases is available; and other guidance you may wish to consider.