the test normally take the best part of a day.
you will have to prepare and deliver a 45 minute lecture. the examiner will normally contact you a few days before to give you the subject. expect lots of questions and make sure you know your stuff.
then you end up chatting about the ppl, what the requirements are, what they are aloud to do. also discuss what an FI privileges are. the best way to swot up for this is to read and inwardly digest LASORS.
then you will have a flying test. this will involve pattering a pre defined lesson ( normally straight and level or one of the early lessons ). this is normally done without any notes. then you will be asked (with the aid of notes) to patter a few other lessons. a quick PFL and a few circuits and then it's back to the club house for tea and stickie buns.
well, that was my test anyhoo.