In response to a question on 20 February 2012, Olfarts replied
According to the owner there were 3 built... The Hutchison van has a number of similarities to the Mayfare van, also built in South Australia in limited numbers around 1948 - according to reports only three Mayfares were built.
There are further similarities with the Smal-A-Van from South Australia which was advertised in The Australian Motor Monthly in 1953. The Smal-A-Van appears to be identical to the Mayfare.
Due to the similarities between the Hutchison, Mayfare and Smal-A-Van caravans, it seems likely that there could be a link between the three. At this point we don't have any documentary evidence for the Mayfare name, and it is possible that this name was given informally to one of the "Mayfares" by a previous owner. The same might also apply to the Hutchison name, but in making this suggestion I am not meaning to question the integrity of the owners of either the Hutchison or Mayfare vans, just wondering about a common origin.