Central locking broke, Vauxhall Astra van?

My central locking broke when I clicked the key to unlock the van, and my passenger pulled the handle at the same time, after that it wouldn't work. I have to lock/unlock manually. Left it a while and didn't bother trying to fix. Now got a new battery so light on key works, but turning key one click and clicking unlock/lock doesn't work (supposedly resets central locking), any suggestions?