We've had our own firework displays at the back of the house, and we've taken the kids to bigger displays. The local council throws firework displays on or around the 5th November yearly, and the incoming Lord Mayor of the City of London always has one by the river (usually on one of the Thames Lighters - barges - near Blackfriars Bridge between the City and Southwark, SE1) a week later on the 2nd Saturday night of the month.
Recently, last year, we had two additional ones at the Olympic Stadium in Stratford, E20 (that's a new one). Fairly spectacular. As it happens the wife is a big fan of fireworks, and the 'kids' are spread out across Europe. The nearest is the eldest, a borough away across the open area we call Wanstead Flats (where Newham Council's firework display goes off, fairs and circuses set up every Bank Holiday etc.