Not lost!
I thought that my work computer’s demise had taken about a day and a half of Visual Basic drudgery with it.
Turns out not. I must have backed it up to the network while in a sufficiently altered state (caffeine, cut that out!) not to have remembered.
Well, that is a good way to start another day of VB drudgery.
Update: Bah. Have to redo it all anyway owing to new discoveries about semantics of supervisor-key fields. Some days it doesn’t pay to get out of bed.