this thread from the archives
If I remember right, what was supposed to be the last ever mid-afternoon bulletin didn't happen because the newsreader got lost on the way to the studio.
seems to suggest the last scheduled 3pm bulletin was on 28 April 2008, and went out as planned. It does sound like the sort of thing that might have happened though - perhaps on another timeslot?
Would've been late December 2012 (as someone mentioned, tied in with the end of CBBC on BBC One).
Odd find, that, though from 2008 - according to Genome the bulletin was only off for about three weeks apparently just so they could fit an Aussie drama and Nick Knowles doc in the daytime schedule!