From the Bolton News, this report..... (It's from one of my local papers - I've seen the paper copy & found the www version for the forum).....
New Year drama as firework sparks roof blaze (From The Bolton News)
Apparently the remains of a rocket have been found...... curiously, though, it seems the incident was at around 6am! A family asleep had a rude awakening, then, but thankfully got out of the house safely.
Here's a case to cite when warning (as we do) about rockets, or other fireworks for that matter, landing in gutters.