A newly built radar need not be the same radar

When a trial involves a new radar or computer, does 'new' mean newly built equipment or an entirely new type?

It can mean either. A later example of the same nominal system may contain enough changes to behave differently from the first installation.

Long gaps between hulls and substantial differences within the Astute-class build program make exact repetition unlikely. A radar can keep its name and specification while incorporating new components, software, or combat lessons. Testing must therefore prove the equipment actually fitted, rather than rely only on the results of an earlier ship.