How can i fix my Ford Mondeo 2001mk3 cenral locking issues?

My central locking on 2001mk3 mondeo locked me out while de-icing other morning! It also intermittantly locks me in while driving, sometimes when i press the window wash & often re-locks itself as soon as i'm initially unlocking. Less often it has also failed to lock the driver door even though the indicator flashes on 2nd press as though dead locking. Please please can anyone help. Lucky I had a spare key.