I think that's 34067, Tangmere. Battle of Britain Class, which included the West Country Class. These are the 'light pacifics', which were evolved from the Merchant Navy Class, which had limited route availability. By reducing weight.
"In order to improve on the route availability of the Merchant Navy class with its 21-ton axle loading, the weight was reduced by 5 tons"
This one is "unrebuilt" and so still has the chain driven valve gear which runs in an oil bath.
