What happened was they had pressure switches built into the handle, right & left, intended to respond to the 'driver'. When they got wet, they would sometimes 'decide' to go round in circles...
The sad thing is, RM also trialed E-trikes, which apparently fared much better, & cost less. But as they had just got rid of the RM Pashley pushbikes on H&S grounds, it was decided to go ahead with the EHCT's.
British management at it's finest.
Bru.