This is brilliant - thank you David for posting this information. There are a number of us on this forum who are interested in the history of the canal boat hire industry.
'Dawn Treader' and its two other sister boats were operated by the Adkins family of Holt Farm, Napton. My second canal holiday was on 'Dawn Treader' in 1977. We had a good week going to Market Harborough and back.
As it says on the brochure extract you've attached, the 'Conifer class' were operated by The Water Folk, a company owned by Alan Picken, who owned a large very eclectic mix of ex working boats.