The police cant do anything, is this right?

About 3 weeks ago my sons bike was stolen from my garden. I reported it but didn't expect much as my son had not chained his bike up. Around the same time, some neighbours and friends were becoming concerned about the presence of a particular van that had been seen several times parked in our street, as well as others. Several bikes were stolen and continue to go missing. Last week i woke up to see the van in my street, and a man jumping into the back of it with my daughters bike! (it was chained up and he had sawed through the chain). I noted the reg number and went right to the police with a good description of the van, driver and the man who took the bike. The police said there was nothing they cold do and didn't even take the reg number from me. I was outraged and made my feelings clear to them. Surely this isn't right? Its blatant theft, surely the police have a responsibility to at least look into this?