Horatio Hornblower (TV series)/WMG

Lt. Bush is a Time Lord
C'mon, someone had to say it. Alternatively, Mariette is one. "Maria" is just the name she took after her regeneration.
 * Or perhaps Archie is one.

Captain Sawyer believed it was Hobbs who pushed him down the hold.
Remember how Hobbs, the man undyingly loyal to his captain, said he couldn't say who pushed Sawyer?

Wellard told him who Sawyer suspected, so why couldn't he? Who did Sawyer blame?

We can rule out Wellard - too small, as Sawyer said.

Had Wellard told him that Sawyer believed it was Hornblower, then he would've said so, probably, since he knew Sawyer for years, Hornblower only for a short amount of time.

The same would've been true if Sawyer had believed it was Archie.

Lieutenants Buckland and Bush weren't there.

So who else was there with Sawyer? Hobbs was. After Sawyer had been pushed, but nevertheless he was there. And remember what mental state Sawyer was in, confusing Archie for Admiral de Brueys. It would be relatively easy for him to confuse the two incidents, especially since the memory of his fall was still vivid when he was there with Hobbs. He could associate the fall with Hobbs, and come to the conclusion that it was Hobbs who pushed him.