A number of additional Admissions Tests are sat by LVI students, usually in the Autumn term of Upper Sixth. Many of these, in particular those for Oxbridge applicants, take place in the half term of the Autumn Term, although some tests, including LNAT and UCAT are sat at external locations on a date selected by the candidate.
Full details of the different tests, dates & deadlines, who needs to sit them and what students will need to do in terms of preparation can be found here.