Just wanted to echo the be careful message. The block I live in was recently burgled as well.
I think this gang are purely opportunists preying on weak doors and inadequte locks etc - makes sense as most older properties dont have modern deadlocks etc. If anyone is worried it might just be worth having an extra dead lock fitted above your current lock. I reckon it will put these types off trying.
Good news that the police are aware of it make me feel a lot better about things.