After lunch we set off towards the lock. I’d seen the red and green lights earlier in the day, but now the amber light was showing, so I got off for the self-service operation. This lock was different to any we’d seen so far. It had the usual buttons on pedestals at each end, but nowhere for a key. I eventually read enough of the instructions to realise that my key went in the controls for the bridge in the middle of the lock. With the key turned, I could close both road barriers which then released the swing bridge. Once I had swung the bridge the lock controls would work.