Pete I can confirm your mystery machine is a Monro Minor or Crunchtiller, the yellow colour and traces of transfer confirm it is a later machine from Mechanised Gardening,Great Gransden, Cambridgeshire; they ceased trading a good few years ago now. The second photo shows the part number MM1 ie Monro Minor 1, most parts for the Monro Minor had similar numbers.I know from the time I have spent helping catalogue them most drawings for parts are held at MERL.