Indeed they can, Doom! Indeed they can.Sometimes those electronics days can be quite frustrating.
Following a quick Email exchange with HW Support today, isolated the problem. They were a big help in confirming the problem was not with their ESC.
Bad "Y-harness." NIB and bad. That's the worst kind. Anyway, grabbed a second one and program box worked A.O.K. PB connects to the fan port to adjust ESC settings. Use a "Y" so disconnecting the fan is not necessary to set the ESC. Yeah, I know, introducing a variable often causes more problems than it solves. Proved that to myself yet again. Good-to-go now though.
Lowered the punch on the ESC so she comes off the line softer. Less initial wheelspin popped a 22mph run, +2mph over yesterday. That's the upper limit of the space available here. R1E is now ready for the big show on an unconfined course.
Cheers. 'AC'