They were probably very confused by the presence of knives and forks and angrily smashed the place up. They then probably half-heartedly 'apologised' via the papers and then were outraged when Pizza Express didn't accept the apology. Doubtless they now boo the restaurant every time they walk past it and call its staff cünts.
I could be wrong about Monty's lady, of course. It might just be a dream I had.