The standard service for ILR applications is up to 6 months.
English Language Knowledge for ILR
It costs an additional £800 for super priority processing (24 hour) and £500 for priority processing (5 day processing, where eligible).
Normally, a limited number of SET(LR) applicants can use the super priority service daily. If the maximum number of customers has been reached when you are ready to submit and pay, the option for super priority will not be available on your application form.