Derek, we looked at Ford chassis codes in
this thread. The standard C11A cars/wagons had 6.00-16 tyres, as did too the C21A. The -DF indicates that the vehicle is fitted with 9.00-13 tyres and is RHD. Note that the scale drawing you have provided the vehicle is described as a C11AD, and is therefore a LHD, as drawn. The C11ADF were 1941 models.