Model Steam Railways

Hornby must be wrong as well....
BR 4-6-2 'Sir Archibald Sinclair', Battle of Britain Class (Air Smoothed), Early BR

Merchant Navy Class
"Opting for a very high pressure boiler, Bulleid was able to make the 3 equally sized cylinders smaller, at 18” and better balanced, resulting in his newly designed Bulleid Firth Brown 6’ 2” driving wheels, which in turn reduced hammer blow to the rails. In 1934, Bulleid had opposed the use of streamlining, but for the Merchant Navy design it suited his purposes, being easy to clean mechanically and hiding the boiler’s external pipes, which in turn meant they could be run for function, rather than aesthetics.
The Hornby ‘Merchant Navy’ will feature a fully detailed air-smoothed body shell matching the detail differences between the different build series, a new air-smoothed tender for the original series and an all-new 6,000 gallon tender for the third series locomotives."

Battle of Britain Class
"Known collectively as Light Pacifics, the Southern Railway West Country and Battle of Britain classes were originally designed as air-smoothed 4-6-2 Pacific locomotives by the Southern Railway’s Chief Mechanical Engineer, Oliver Bulleid. Designed to be lighter in weight than the similar Merchant Navy class, they could be used on a wider variety of routes, including the Kent coast and South West of England."