One of them, Rear Admiral Simon Lister, is in charge of this complex programme, and as he took me round the cramped corridors, past the nuclear reactor and down into the sweaty machine rooms, he acknowledged this was a prototype and there was always going to be some "teething" issues.
This is roughly 200 metres square, and has corridors running along virtually its whole length which are lined with relief sculptures of a grace and precision to take the breath away.