Your favorite platonic pairing:
This is such an easy choice. Lucas and Ros–hands down. The camaraderie and banter between these two was fantastic. You also always knew that they would always have the other’s back–he did attempt to go back for Ros and the Home Secretary.
Me, My Thoughts, and Richard Armitage 
YES!
Totally agree. Richard and Hermione are both so talented and really have a nice onscreen chemistry.
(And she has called him “sublime” which endears her to me even more).
Somehow, I felt more safe when Ros and Lucas were on the job, even though I am not British and they were fictional characters. 😉 And I sorely missed Ros in S9. 😦
As you said, Lucas and Ros always had each other’s backs. Colleagues are OK..
Setting aside the whole Lucas/John Bateman issue of season 9, one of the things I missed most was the tie between the spies. I was a fan before Lucas–having really enjoyed seasons 1-6–and up through season 8 they were a tight knit group, even when someone died and new people came in. Then it that ninth season the whole thing started to fall apart. I missed Ros too. 😦
I was so sad when Ros’s character died in Spooks I really liked her energy and she would often have the best lines of the episode. .I didn’t think it was a fitting way for her to go, although her funeral was touching. She deserved a better exit. That’s why I like season 9 for Lucas, because he unravelled all through the series and you just knew he was heading for a horrible demise.
I also appreciate her relationship with Lucas. It would have been so easy to create a sexy atmosphere/tension between them, and yet I think mutual respect was a lot cooler. They didn’t go down the obvious path.
I was sad when Ros died too. I actually thought the way she went was quite heroic–she could have just left the home secretary and saved herself, but instead she did the honorable thing. I think I could have gotten on board with the unraveling of Lucas into John Bateman if it had been done better (not RA’s acting but the scripts). That particular storyline needed more than the 8 episodes it got.