Thanks Andy!
A few more bits have turned up over the last couple of days (Thanks Richard!), and I’ve realised that I’m missing three models (at least) from the list (D,E and F). I’ve also reviewed the pictures I’ve taken over the last year or so, and realised that I have some better pictures to add for some models, so I think there will be a couple of further updates over the next few months.

I’ll check tomorrow, but I don’t think that the Autogardener rotor box will fit the Mk ix. Some odd bits do turn up for the mk ix occasionally, but not often. Mine came with both the plough and the rotovator, but the rotovator was worn out (long term job, as I have to make anew rotor shaft).
Chester Hudson did have some bits, but I don’t know what he has left.