so at least if the police find it they’ll know where it came from.

[N.B. for U.S. readers: postcode = zip code]

↓ Transcript
1. (wotcher! how are you?) [rather down, today]
2. (I'm sorry to hear it. What's wrong?) [my house was burgled]
3. [no!] (yes! everything I had is gone]
4. (that's awful) [yes, and I took all the precautions]
5. [locks, bolts, alarms]
6. [_and_ I had my postcode etched on every window]