Lockdown boredom... I'm still here!But only holds on the initial 0 for a few seconds before going into the error code on repeat
Your mates' wife may be in luck... This page says the M45 was only introduced in 2018, so it can't be too old - maybe under 2 years old?:
Products | EBC Bikes (ebco-ebikes.co.uk)
Rifling through my draws, I've found an Ebco manual that includes the M45 model. It states:
All electrical components inc battery are covered with a 2-year warranty (battery limited to 500 charge cycles).
If error codes appear on the display, refer to the error code list (in the manual, a similar but shortened version of the one vfr linked to above - nothing about "0Hot" though) and contact your dealer for diagnostics.
Elsewhere, FAQ says "the motor can overheat on very steep hills, but the built-in heat sensor will automatically shut down the system before any damage can occur to the internals of the motor".
As your DP27 is booting-up properly, do you think your "0Hot" message may mean "0" mph, then "Hot", as in an overheat event occurred? Okay, so I'm clutching at straws here...