For anyone curious, I washed me bike, covering the controllers with plastic baggies, double checking all the connectors, and leaving the battery on, making sure the plug in part was closed.
Hosed it down gently, avoiding the controllers as much as possible, then doused it in Muc-off. Let it sit for a bit, brushed it around, then hosed it down again, before applying some bike protect. (then did the whole degrease and lube the chain thing).
All in all, bike is mostly clean - the tires are still a bit grimey - and all was good when i went on a quick test ride today.