I know what u mean, but they are clearly waiting on something ie references, police checks or results. It quite clearly states in the letter - (Staring a university course can be an exciting time but it can bring with it some anxiety, for that reason I would like to invite you to an information and getting to know you event.) Reading that, it seems that it is very much aimed to those who will be STARTING this year. I am on reserve and i received mine last week 30th of June. Personally I have a place at UU which has been confirmed so I am sorted either way, however, there is a reason behind why a reserve offer candidate received one and conditionals haven't!! The only other thing I can think it might be is if the references they have obtained for some ppl are not up to scratch of something? but I really can't get it at all.