ebike with switchable throttle - legality?

[gmaz]

I have a home built ebike with a throttle which yeah I know is illegal on the roads, so I was thinking if I inserted a road/off-road switch into the cable, would it still be illegal on the road if the throttle was disabled?

Would it come into the same category as the ebike motors that are limited to 250w but can be "hacked" for more power off road?

[Bacon Is Proof]

Is the motor "assist" limited to 15.5mph?
Just because you're not on the road doesn't mean that you're not riding an uninsured/taxed/licensed motorbike.

[TheFungle]

Just stick to shared use paths and you'll be fine.