the date of the deadline differs depending on when you get your last offer. so even if you met the january deadline it doesnt necessarily mean you will have all your offers by the end of march. i sent my ucas form in before xmas but cos of interviews and stuff i didnt get my last offer til the end of april so i then got til about the beginning of june to make my choices even though other people in my class only had til march/april. it just all depends really, but it will tell you on the letter when you receive your last offer. also i think accomodation deadlines are different for each uni, again i think you get a letter about this (cant really remember, but you will be told)