Ransomes Minor Mk 1 to 5 ??????

Hi All

Whilst I have a Minor Mk 6 & have seen Mk 7's I would like to know more of the earlier ones, ie did Mk's 1-5 exist & any  distinctive features, year of manufacture, scarcity  etc.

In the Ransomes book by Brian Bell page 104 has a picture of a Minor with the fuel tank between the handles, there is no mention of date Mk  No. etc.

Can anyone enlighten me & help with the above info.

Thanks for your help.

Clive