Selection Problem

[DaveMDarcy]

Hello,
I'm having problems trying to select the pitted areas of this model. I normally use the fill selection or phong break selection tools for this sort of thing but nothing is working well on this particular model. I did not create this model myself, it was supplied to me by a CAD product designer. Any advice on how to quickly make accurate selections on this would be very much appreciated thanks.

https://drive.google.com/file/d/1TgJOvS8B59z0BwEZjLkYcUfjQERZZg87/view?usp=share_link

Kind Regards
David