Actually we can supply an electric handbrake as an option. We looked into it as part of PACE 427 development. So our existing handbrake system can be upgraded to a calibrated electric operation.
I would be wary of some of the "hotrod" style systems as they are complex device.
Should not be any concern for registration compliance as all the systems employed still use a mechanical system just with an electric actuator, so meet all ADR requirements.