Cental Locking - Golf?

I have a VW Golf 2005 registered. I've only had a month and the centeral locking on the drivers door has stopped working. If I unlock the car once nothing happens, if I press twice all the doors and the boot open appart from the drivers door! If I put the car in hte door it will unlock that way, otherwise I have to climb in the passagne door and open from the inside but them sometimes the little red key is locked on the inside of the door - any ideas. The manual has section 3.1 missing - so can't read that!

Thanks