G'day prd, Fashionista Shaun, and all patinaristos (I made that word up)

I think that is the best approach here prd.
This is, as you know, a controversial issue. It's not a simple one ...

For example, some sources will say rust is a patina on metal surfaces.
I sometimes think that too much rust (or corrosion) destroys patina,
and this points to a more extensive restoration.

In this case the tank and large parts of the base are good.
The handle bar is rusty though. Some would say this patina should
be preserved. Because TADs are so rare - and historically significant -
this would be the approach I favour (in this case).

But ... some would argue this is a marginal case - too much patina has
been lost [by their definition]. I understand that case too.

I know Gordon Brown discussed this piece - the most valuable piece
of furniture from Tasmania's colonial past. Had it been fully restored,
it would have been valued at half its current value:-

[Linked Image]

The lesson, for me, is whatever the decision is, it must
be taken in a considered, serious way.

John Lennon seems to have gotten away with this one - worth
much more than any 'original' Phantom ...

[Linked Image]

The reason, though, goes to provenance.
... And it now has a new patina that should be preserved.

A very challenging issue.
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Jack