There are a number of countries that have or are interested in taking up "EN15194" guidelines for their own e/power bike regulations albeit with perhaps a few localization tweaks.
We in "orstrayleeya" now have a majority of states that have either legislated for same or have indicated intentions to do so. The whole country was restricted to 200W but even in unlegislated states now I believe bikes tentatively legal according to EN15194 are acceptable (don't know about insurance litigation though).
The fundamentals touched on in this thread are straight forward and your UK EN15194 assumptions are applicable to most implementations...
*No PAS, NO GO; end of story.
*PAS must kick in at 6km/h>.
*PAS must shut down the motor around (legislated specifically) 25km (of course you can still pedal faster than that)... PAS should degrade towards that speed.
*Technically twist / thumb throttles are allowed but must be programmatically deactivated above 6km/h. This allows one to start moving from stationary via throttle ie safely from traffic lights etc.
*If a thumb / twist throttle when turned aggressively (ie high) does override PAS the bike is illegal (with exception of 0-6km/h). So that's all a savvy copper has to do to test it.
If there is a button or other mechanism (ie display option) that can override PAS the bike is illegal (ie if the rider can override PAS just as one could with an GM overriding throttle).
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So until GoldenMotor uses all their skills shown in the design of their current e-bike products apply the above EN15194 requirements programmatically into their controllers they will become further and further behind other manufacturers regarding global certification and saleability... note its easy to build an illegal e-bike but becoming harder to RESELL them.
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Untested as far as I know, it is fair to assume that if off-bike programming of a controller to swap between PAS / non-PAS modes is possible this would not constitute a breach. So if the PAS on / off were accessed only via the USB port this would be a good feature retaining all the current you-beaut GM features.
*Most EN15194 implementations mean the cruise control button is illegal. As above option should only be available in non EN15194 USB profile.
One area of inconsistency between country jurisdictions seems to be in the interpretation of or acceptance of constant / maximum output limits, if they are both applicable, and how they are arrived at (ie their may be a 15%, perhaps, allowance for the difference between constant output and intermittent maximum output limits). This at least sensibly eases the futility of a need to try and lawfully match an output limit exactly.
Always there is a vocal multitude who, with a lack of intelligence I might add, brag to all that if this and if that then they can trick the coppers. Well slowly various forces around the world are becoming more savvy about how to detect a probable e/power bike law breaker.
Basically if you ALWAYS APPEAR to be pedaling on level or rising gradients or when taking off from stationary then you will probably not be harassed by the cops. This in particular applies to on road / shared track speed junkies with over powered bikes - just keep on pedaling like hell even if not actually assisting very much; at least make it look like you are.
Of course in EN15194 jurisdictions a copper with nothing better to do will definitely notice a bike with one of those dirty great big magic pie motors shoved in amongst all those short spokes!
Lastly, at the end of the day it may not matter if your bike is a "little bit" illegal. What really matters are the more and more savvy police and insurance companies that put the onus on you to prove your bike is legal when an accident and perhaps injury to others or property is involved - then it can become very expensive.
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Even after the incredible bad luck I have had with a GM SmartPie3 and lack of response to my last "within warranty" request for a replacement I would probably buy a new SmartPie4 if only it would include EN15194 USB setup options. But now I have had to look elsewhere for a replacement.