Hi,
That is a 1954 / 55 G2 350 Bullet, I have owned an identical machine for over 30 years [languishing and needing attention, but runs]. The forged swingarm lugs on the frame pin the model years down - this type of frame is quite rare, only being made for one year before the all welded frame came along. I also have a 1955 500 Bullet using the same type of frame, the flat toolboxes are correct Redditch tinware.
Nice find!
B.W.