Sorry - too much English, not enough Euro - let me try that again. The cathedral scenes were shot in Bristol, so the movie makers hired in two London buses to make it look like London - they're the two buses seen in the screencaps. The local bus company was the Bristol Omnibus Company, who mostly used Bristol-built buses, painted green. In one scene you can just see a local green Bristol bus, possibly a Bristol RE.
Of course if you go to Bristol now they're pink and purple