An Anon the other day pointed to this.

Feb, 18 1996 @ 2238 GMT a bomb blast destroyed a London bus. I will try and find it but Anon mentioned that the B7 may refer to the battery, engine etc. I will try and find it. Not sure if that has anything to do with Q's post or not.

http:// www.independent.co.uk/news/armed-guard-on-ira-bus-bomb-suspect-1319854.html

I think I found it

http:// www.trafficdelays.co.uk/waterloo-bridge-south-london-cctv-traffic-camera/

http:// news.bbc.co.uk/onthisday/hi/dates/stories/february/18/newsid_4165000/4165719.stm

The bus had travelled over Waterloo Bridge along Lancaster Place and was passing a Ministry of Defence building and turning onto Aldwych when the bomb exploded

Feb 18, 1996