Ah – my question answered. Thankyou!
Mine is the older sort with a press-button fob only to lock/unlock the doors, and the driver's door can be unlocked mechanically.
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Years ago I had a Vauxhall Chevette, back when it was all mechanical locking, doors and ignition. I am not sure if it also had a steering-lock. One Sunday evening, I and a companion were the last to leave our caving-club, some sixty miles from home, and we could not find the keys anywhere.
The doors were unlocked, so that was a start. A local member with access to the lost-property cupboards tried all the keys in there (quite a number as I recall) plus some spare keys he had. No luck.
Having led a sheltered life I knew nothing about hot-wiring cars; but as a last resort I removed the cowl from the steering-column. By complete luck we found the lock's shear-screws had not been sheared. Using pliers very, very carefully, I was able to remove the lock itself and use a screwdriver to operate the ignition switch. Once home I emptied the car and left a cloth draped casually over the stripped switch, until I could fit a new lock a couple of days later.
The lost key turned up a couple of weeks later. I had hung it on a hook in the changing-room, where someone had innocently then hidden it by hanging a towel on the same hook!