Hi Daniel if you go to the "members' area" of the website homepage, select "directories" then "Membership List (Online and Printable)" - you can the enter "leisure" and you will find the member from Hungary, referred to by Eric, who has converted a Leisure 17. (and email address)
In addition there are a couple articles (Newsletter 22 and Newsletter 44) - if you can download them from the JRA website - there is a bit of historic information as Vincent Reddish describes the conversion and design of sail for one of his earlier boats (a Leisure 17).
Magazine #77 (June 2018) carries a short article in which a member describes his Leisure 17 conversion, mainly describing structural details etc.
The name of that boat is Escapade and if you search "Escapade" on the above membership list you will find the writer of that article, and his email address.
Let's know if you have problems downloading any of these articles.