I doubt there will be a massive general crackdown, there aren't enough cops. Reducing antisocial ebiker behaviour on high streets is about all they have manpower for. Sneaky Sunak is doing the best he can to not make waves.
The BBS01B has 250W engraved underneath the motor. My plan if challenged is to flip the bike over, thus making view of it accessible... it's also engaved large therefore accessible for shortsighted cops to read. I'd also show them the speed limit on my display. I might even let them ride it around a bit, if they give me their police car keys or the equivalent (ever increasing, it's a money pit is cycling) of my bike's value in cash.
Two years ago, ebay had laminated paper stickers with speed limit as well as power. How about a cheap £5 custom engraved plaque? Engraved with:
BAFANG
Model: BBS01B
EPAC according to EN 15194
250W, 25km/h
There are oodles of trophy shops near me, where I could pay more than twice as much. There's already a CE mark on the motor (or was, there has been much riding through rain and mud since I looked last). I could simply araldite or superglue+baking soda the plaque to the motor.