Today I rode on the Class 458/4s a highly refurbished version of the similar looking Class 458/5.

For those wanting the unit numbers I rode on, they were:

458415
458421

These trains currently are running on the London Weybridge via Hounslow diagrams and will be for quite a bit, until they move onto the London Portsmouth routes for their services

First Class is declassified on these units for now, so for those going to ride them, do bare in mind that you can sit in the First Class Compartment for free!