Good morning. This very interesting bust is effectively a depiction of Democritus. The reference to Orazio Marinali is incorrect. in truth it is a reduction of the bust of the philosopher sculpted by Giusto Le Court and today in the Ponce museum.
This work may refer to Le Court's pupil: Enrico Merengo. the work of the V&E is by Alvise Tagliapietra, a pupil of Merengo.

Is there an image of the Democritus bust at Ponce online? It does not appear to be accessible via the museum's website, though I understand the museum also has the pair to the Democritus bust, Heraclitus, also by Giusto Le Court. Heraclitus was known as "the weeping philosopher."

The Ponce bust is below (clicking on the image will enlarge it). It is very close to the V&A bust, and at least formerly it was attributed to Marinali. Our bust is clearly related to it:

https://bit.ly/3xKxJlD

Le Court, Merengo and Tagliapietra were all active in and associated with the Venice/Veneto area, so one could reasonably attribute this bust to Italian (Venetian) School should the collection so choose.

See the following for Orazio Marinali's stylistically different version:

https://padovamusei.it/it/musei/museo-arte-medievale-moderna/collezioni/scultura/democrito

This collection has five marble reliefs of heads representing various humours by Marinali:

https://bit.ly/3xPf3Bg

A comparable Marinali bust of a satyr is at the Bowes Museum:

https://bit.ly/3z9kWcR

This kind of bust, common in Venice in the second half of the 17th century and early 18th century, is known as a character bust. Le Court (who was of Flemish extraction) is considered the originator, but there other noted exponents like Marinali.

There *were* other noted exponents like Marinali.

Here are many things to clarify.
The V & A bust, with pendant, was rightly attributed to Alvise Tagliapietra in 2002.
The Padua corset is not marine, but a bust of the Bottega of Michele Fabris called the Ongaro.
Marble reliefs are not marinal: rightly attributed to Giovanni Bonazza a few years ago.
The Satyr Bust: it is not Venetian, the attribution is incomprehensible and wrong.

It appears that the V&A, the Padua Museo d'Arte, and the National Trust (which owns Hughenden Manor) are not aware of or have not accepted these attributions to Tagliapietra, Fabris and Bonazza, respectively. Who made them?

The original question posed, which concerned the identity of the subject, has been answered satisfactorily in the affirmative. The matter of attribution, which is rather more complicated and would require additional evidence or documentation, can be left for another discussion. Thus, pending the input from a Group Leader, I would think this is ready for recommendation to the collection.