A question has been asked in a comment, to which I don't know the answer.
The lists members are elected on a party basis. What happens if a list member changes party allegiance or is expelled from membership of the party?
I don't know. Do they remain AMs or is their place taken by the next in line as would happen if an AM died or resigned?
(NB I am asking the question for curiosity's sake not because I am plotting to nobble any particular AM - yet!)
Thanks to Peter Black AM who not only gave a definitive answer to the question, but also found an example to prove the point. Rod Richards was a list member who sat outside his party group. If a list member leaves his or her party then they stay an AM. Thanks again Peter.