Bristol Lodekka FS6G/Eastern Coachworks of Thames Valley Traction, followed by an AEC RT of London Transport's Country Area
What's that through the window?
London Transport Country Area AEC Regal IV RF/Metro-Cammell follows a Bristol Lodekka FLF6G of Thames Valley
Thames Valley Traction Bristol Lodekka FS6G (rear entrance)
...but in the next shot it's changed into a Lodekka FLF6G (front entrance)
This is Windsor railway station, by the way; the Duple Commander bodied coach in the background is either an AEC Reliance or a Leyland Leopard.