Pollack-tier books on Heenan, Sayers, Mace, Belcher, Cribb, Broughton, etc?

The London Times did cover bouts for such as Cribb.

 

They just reprinted reports penned by somebody else, not by their stuff reporter (they didn't have one). You could find the same write-up in multiple other London newspapers.

Example:

1807-04-09 London Times (page 3)
Round 1. After some cautious sparring, Belcher hit Crib left and right on the head and body. Crib returned a blow slightly, and attempted to rally, in doing which he closed, and Belcher threw him. 2 to 1 on Belcher.

1807-04-09 Morning Advertiser (page 3)
1807-04-09 The British Press (page 3)
1807-04-09 The Courier (page 4)
1807-04-09 The Morning Chronicle (page 3)
1807-04-09 The Morning Post (page 3)
1807-04-09 The Public Ledger, and Commercial and General Advertiser (page 3)
1807-04-12 Bell's Weekly Messenger (page 5)
absolutely the same description of round 1, word for word.

 

1809-02-02 London Times (page 4)
Round 1. Some sparring; Belcher threw in right and left, one of which blows told slightly; Crib returned one, also slightly, and Belcher was thrown.

same round 1, to the letter, in
1809-02-02 Morning Advertiser (page 2)
1809-02-02 The Morning Herald (page 4)