Actually Mogs are not as bad as they were. Have a look at the owners club website:
http://www.mmoc.org.uk/
The 'messageboard' is the forums, some helpful characters just like here.
Example:
http://www.mmoc.org.uk/index.php?nam...wtopic&t=26593
You could consider a commercial: van or pickup, both morris and austin versions, Cowley and Longbridge, just like the 75.
The main thing is tin worm: they can rust badly, and be bodged to fix it. Other than that they are mechanically simple and therefore a breeze to fix. But the design is almost sixty years old!