Why later Type 26 batches should remain similar

Might the Batch 2 Type 26 frigates differ significantly from Batch 1?

No. The plan is to keep the batches as similar as possible so they remain cheaper to build and support.

Batch 2 is not expected to become a substantially different subclass. Common equipment and arrangements keep construction simpler and cheaper. Repeating the design also limits additional training, spares, maintenance, and infrastructure burdens once the ships enter service. Production commonality can matter more than inserting every possible later improvement immediately.