Sturdy doesn't sound heavy enough for Kunming. Go buy another ulock twice as heavy with a spear shaped key and use both. You also need to find someway to lock your nice new battery and soon.

Thanks for the advice. When you say I need to lock my battery, Do you mean something other than locking the bike itself? Are they easily removable?
Does anyone know how e-bikes are usually stolen? Are the locks picked/hacked or cut off or is the bike just lifted onto a triuck or something?

locks removed and hotwired. u locks are rgid and easy to break with power jaws. scooter types can get a metal strap that goes around battery box that locks

Battery locks look like this: www.aliexpress.com/[...]
Some usually replace the strap with a chain. You usually only need to remove this lock once a year to replace the battery and they'll know how to do it at the shop.

On top of the U lock, get an additional lock that isn't the same model and type. I recommend one that uses a flexible key

To try to avoid getting your e-scooter stolen, keep it in sight as much as possible and lock the wheel and steering and put on the alarm even if you are going inside for 30 seconds. Also, always park in designated scooter/bike parkings. They won't guarantee that your e-scooter will be safe, but you'll lower the chances of having it exposed.

Great advice all. Much appreciated.

alarms dont do much, they pop the seat lock and flip the kill switch before they hammer the lock. even if the bike looks bad they will try to take it just for the battery, disc brake, and susp springs.

park inside university or 小区 parking garages, if you pay for charging parking its always closer and in eye view of the guard, and they give you a numbered card that you have to return to them for release of the bike.

alarms dont do much, they pop the seat lock and flip the kill switch before they hammer the lock. even if the bike looks bad they will try to take it just for the battery, disc brake, and susp springs.

park inside university or 小区 parking garages, if you pay for charging parking its always closer and in eye view of the guard, and they give you a numbered card that you have to return to them for release of the bike.

alarms do a great deal, to annoy the hell out of people, but little else

No Kunming police gonna give foreigner hard time on e-bike. Just smile and speak English. It is good to have register certificate, but not necessary. You should get very strong lock, maybe two of them, from taobao.

I'm going on holiday abroad for 6 weeks. I've been told that if e-bike batteries don't get charged at all over a couple of months or so they "die" and lose their ability to be recharged. Does anyone know if that is true or not?