People at Bristols and/or AM were probably of the opinion in early 1930s that 18 cyl engine, that will weight more than 2000 lbs dry even in the 1st iteration is a step too far? For me, with Perseus in production (= the tooling for sleeves and other tiny bits is already purchased), skip the Aquila and Taurus all together, go straight to the 14 cyl 'big' engine (pre-Hercules) by 1935, and 18 cyl derivative by 1938.
Thus there is an almost-Centaurus in low volume productionn by 1939-40, and in mass production in 1941. Graft the initial engines on the alt-Fulmar, and later versions on Typhoon, Tempest, Barracuda and Firefly. Make a twin multi-pupose A/C with 2 x 2000 HP radials, or/and 'Victory bomber' with 4. The 'pre-Hercules' can be used from day one on Halifax (seems it was a better bomber with Hercules aboard), Wellington and Whitley (no Tiger version), perhaps also on alt-Beaufort, since there is no Taurus around.
Earlier series/mass production of the 'Hercules' might also bring about a 2-stage supercharged version, Bristol snatched several altitude records with 2-stage supercharged Pegasus between the wars.