Rereading some of the above I noticed:

I cannot get a scooter as we have no place to house it (1st floor flat).

We have used Lin's scooter almost exclusively at the WVA festival, and it's obviously not too practical to to try to live in a 23-foot camper with a scooter inside. And the weather tends to include a fair amount of rain, sometimes sleet and snow, an occasional tornado warning, etc.

Our solution to providing some "environmental protection" for the scooter while it sits outside at the festival is --

--- DISGUISE !!!

A cover for a medium to large barbecue grill, readily available even at Wally World (and probably at lots of lumber yards) is an almost perfect fit for her 3-wheeler, and sitting on the patio in it's rain suit it looks almost like a barbie-kew grill.

Of course it would depend a little on what kind of neighborhood you live in.

Most of the scooters I've seen do have an "ignition switch" with a key that can be removed, although on some the "key" is so rudimentary that a broken popsickle stick would probably suffice to turn them on. Most mobility chairs appear not to have a "lock" of any kind, on the assumption that someone's always sitting in them I suppose. Auto parts places have "disconnects" you can use to connect/disconnect a battery to give some protection against someone "unauthorized" turning on and taking off with a chair, but it would require some (fairly minor?) installation to get the keyhole in an easily accessible place on the chair.

John