Ok, today as copy&paste (or print out and type-in), no conversion seems to be needed:
The Melarkian, version 1.01, by Paul Panks. From http://www.ifarchive.org/indexes/if-archiveXgamesXsourceXbasic.html (http://www.ifarchive.org/indexes/if-archiveXgamesXsourceXbasic.html)
EDIT: THX to @SuTeKH/Epyteor (http://www.cpcwiki.eu/forum/index.php?action=profile;u=466) now even better.
As extra bonus I add the SNA now.
Enjoy :)
For reasons unclear to me, Winape crashed when I tried to use this SNA.
I was however able to use it's "read basic" and "auto type" option to grab the code
I have attached a copy of the game as a dsk, in case anyone else is having trouble