Shall I chase my application?

I attended an assesment day at a top City firm in late August and thought it went really well and as such I was hoping for good news on 1 September. However, contrary to what I thought I’ve heard absolutely nothing.

Do you think I should just accept that I’ve been rejected or should I call the firm to find out what’s happened? Have most of you heard back from all the firms you’ve applied to or do these things drag on for quite a some time?