I got some 3M Dual Lock, it's a lot stronger than normal Velcro. I did use some double sided carpet tape just to make it stick better to the plastic.
Send me a pm and I'll send you some.
It's easy to reach on the left side, I did remove the bell and the front plastic shield since they got in the way.
I don't really worry about theft the scooter goes in the hose and at work I just take it into my department and fold it down and place it out of the way.
I thought about a chain and a lock, but haven't done anything with it yet.
Prep both surfaces with isopropyl alcohol and use this stuff -- it works wonders:
3M Dual Lock Reclosable Fastener SJ3550 250 Black, 1 in x 4 Ft https://www.amazon.com/dp/B07STXS463/ref=cm_sw_r_cp_apa_i_h45PDbSXXQF1Z