Pretty sure that small hatch is from the 223. It's sand-coloured in the pre-paint workbench pic. The 'rectangle with bottom corners missing', left of the four Centurion 'hinges', is also 223, B7.
The tiny round part in the corner to the left of the lone Scammel ramp is 232, but may not be on the original, as it's also sand-coloured.
The panel Martin's used under the '351970' marking is from the Panzer Kampfwagen IV, but again may not be studio-correct. It just looks a slightly different shape and length on the original.