Again, I ask you what the Taranis requirements are. Why is an F-35B payload a comparator? We're not replacing the latter's capability in a UCAV, to my knowledge.
Once again we seem to be conflating the RAF's requirement, for a Future Combat Air System, with a confusing argument (or straw man) about why the C isn't in the line up. The C variant is best suited for a conventional carrier, which we won't have. The A variant has 95% of the fuel load and range, with the same payload and none of the parasitic weight of the C.