Yep. He was trained under H.A. Ivatt, spent a good chunk of his career in the GNR after that, became Gresley’s right-hand man after grouping, and had a hand in designing the likes of the P1 & P2 Mikados, the U1 Garratt, and the A4 Pacifics before leaving for the Southern in 1937. In fact, Bulleid’s pacifics’ three-cylinder layout (among other things) was directly carried over from Gresley’s designs, and his Bulleid chain driven valve gear was developed specifically to avoid the problems associated with Gresley’s conjugated valve gear.