My review of episodes 1 and 2. (spoilers)

As said in the first post about this show, why would the Royal Navy not send one of their own to investigate?

The technical details are bad at times. I was in the USN for 20 years and served on four boats. Times change, but pressurized water reactors are not changed too much since the 1990's.

It looks like they might have got the forward part of the sub right, the engineering spaces look all wrong.

My gripes;
1. The sub's screw has lots of cavitation bubbles.
2. I never heard of "headaches from low oxygen content" on submarines; especially soon after boarding like the detective does. A sub normally takes every opportunity to ventilate the ship when on the surface, so they would have had a normal atmosphere at the time.
3. The sub's doctor says it is hard to keep track of time on a submarine. Everyone watches the clock (wristwatch) on a boat. Their lives are run by the clock.
4. There is a HRA sign attached to a pipe in an engineering space?
5. Lights go out and there is a small nitrogen leak right after the scram? The sub takes an angle right after the scram followed by a serious loss of depth control.
6. A reactor scram does not cause an immediate loss of power to the main engines.
7. It takes minutes for the battery to supply power?
8. A sub should not sink when the EPM stops, unless their trim control is as bad as it looks.
9. The XO whines like a middle-management baby; in front of the crew.
10. The sub's rig for dive sucks.
11. Air comes out of the ballast tanks during an emergency dive. Vents are always closed when submerged
12. The engineer is worried about a melt-down if they restart the reactor. WTF?
13. The RPCP looks like a PC gaming console. The control rods withdraw wicked fast. Reactor critical to the POAH is also very fast.
14. A Sailor worries about a reactor meltdown after loss of cooling water. Not going to happen especially on a reactor with a high water to metal ratio after it is cooled down and placed in layup for maintenance.

For a soap opera, it's not too bad.