I echo the sentiments of all here Bro', hope they catch the bastards, doing whatever they did on your kids beds is probably worse than losing material possessions, quite what these people think they achieve in doing so is beyond me.
I think it's difficult to label it as a UK problem as it can happen anywhere, but I think it's true that most likely these were young people doing this and they're a product of the lack of respect for other people and other peoples' property that lax education and discipline has created in this land. Thankfully, touch wood, I've never been burgled but that's probably because I've made sure I installed an alarm in any house that I have owned.
Thoughts are with you mate, hope they get caught soon.