Does the centre of the ignition barrel pop out when the key is removed? There us an internal spring which sometimes breaks causing this,if it doesn't pop out your central locking won't operate,it sounds like your ign.barrel is getting worn,have you tried your spare key? On no account spray these barrels with wd40 as it seems to totally jam up the internals of the lock,if you do get a key to operate my advice us to keep it in at position 1 until you can get a new barrel ordered from a dealer,you will need your V5 and some ID,if your key looks worn then would order one also,sorry but it is an expensive business and expect a large bill,good luck.
cdc
April 2014