This^^

I cannot find a scan of the Reliant owners manual, but I could find a scan of the sales brochure.
On page 13 of that brochure, under "standard safety features", it brags about an impact-actuated fuel supply shutdown relay.

I cannot speak directly to K Car stuff, but I maintain a fleet of 2nd gen Ford Escorts that have this exact thing.
In the Fords, it is a simple inertia switch located in the trunk that pops a button up [thereby interrupting the fuel pump circuit] if it gets jarred.
This need not be an accident - It can be popped by something as mundane as running over a speed bump too briskly.
I imagine it might also be tripped when being towed/trailered to someone's house in barter for work done on an another car.
In the Fords, you simply press the red button back down to reset it.

You might consider investing $9 in a used Reliant owner's manual to direct you to a layperson's description of where to find it and how to reset it.