Hi Dan, thanks for replying.

Yes, I was pressing the clutch - to the floor!

I haven't yet been able to try locking/unlocking via the fob. I don't take it out of my jeans pocket until I lock the car when I leave it, and getting it out of said pocket whilst furiously pressing buttons and waving the people behind to go by has proved too difficult! I'll take the key out and try it next time (though I won't be testing your theory at the traffic lights, I think the driveway sounds like a better option!).

I'll let you know if it works.