"A dull, decent people, cherishing and fortifying their dullness behind a quarter of a million bayonets."
- – George Orwell, Burmese Days
The Praetorian Guard are Africa Theater British soldiers in SPEHSS. They wear the classic redcoats with matching pith helmets, so they look rather classy and fucking manly as hell. Apparently at some point in time the Praetorian's decided to do some fucking manly shit for the Empruh, so they went to an uninhabited world filled to the brim with Orks with nothing but their bolt action flashlights and a handful of Tallarn guardsmen to back them up. While this bravado makes even the Mordian Iron Guard look like delicate flowers by comparison, needless to say the Praetorians lost a few major battles, the most notably the last battle titled The Massacre at Big Toof River, underestimating the numbers of the enemy and being wiped out to a man. Funny, sounds reverse to what happened to the British army in real life against the Zulus in Africa. Good luck finding original models for them these days outside of Only War though.
Aunt Vicky (Victoria Lamb) makes some awesome lookalike Praetorians (as well as Savlar Chem Dogs, Mordian Iron Guard, Drookian Fen Guard and, of course, the Spanish Inquisition). Check her webstore here.
Alternatively you could just buy a box of 38 "Zulu War British Infantry" from Perry Miniatures for around $30, with matching Rough Riders. Perry Miniatures is notable in that they've actually done subcontracting for GW.
Another option is Anvil Industry. Despite costing slightly more than GW Cadians they’re high quality, completely modular and even make Maxim guns. They also have gas mask piths so you could make a Praetorian siege regiment and play them as DKoK.