313001 ought to be a candidate for the NRM - being the first of it's kind ?
Really the NRM ought to have claimed one of the prototype PEPs - which given they weren't scrapped until 1990 it's inexcusable that they didn't.
Definitely one of the PEP units should be preserved - if only because it was the point at which BR's fundamental approach to EMU design changed, moving away from a simple 'motorised' Mk1 carriage with slam doors and instead onto a design that allowed for carrying a large number of people with minimum dwell time at stations.