DON'T GIVE UP!
Why do people think Minis are stolen so often?... It's just so easy to make a profit from doing so.
The shell isn't flushed down the loo like your daughters dead guppy -not only are the parts sold on but the shell has all identifying marks removed & is sold on as a bare shell or with a V5 from a different car.
The only people i can think off who might object to your efforts are those that are just too stupid to realise it reduces the likelihood that their Mini might be stolen.... or traders who don't care as they are making a profit from the merry-go-round of stolen parts & shells ( i wonder if the ex-staff of Jack Knight shed any tears when Minispeed closed down?).