In 1955 the book Okara the Hunter by Frank Denver appeared in Nelson's Panther Library, a series of various stories designed for use in schools..
It is a 'one-off' story of a young boy rescued and brought up by an African family.
At the sale of Reginald A Martin's books in 2002 (Source 4) the name Frank Denver is listed as one of his pseudonyms.
In 1967 the popular Television series Daktari gave rise to some 'spin-off' books.
Two of these, The Pintu Dogs and The Happy Hippo, were written by Reginald Martin, using the name Frank Denver.
The search of the internet we made in August threw up another batch of books under the Frank Denver name. These were all published in Holland and were children's westerns.
It seemed likely that they were by Reginald Martin, but there are some doubts . . ..
The books advertised are all published by Kluitman, Holland. All are described as Kluitman pocket western kinderboeken.
They are all described as being in De Kid Van Arizona Series.
Jacht op Joe Cheyenne; 1978; 160 pages; illustrations by Gregory Peters; J1318; ISBN 90-206-1318-9.
Schoten aan de Rio Toro; 156 pages; illustrations by Gregory Peters; J1322; ISBN 90=206-1322-7.
Vogelvrij Verklaard; J1326; ISBN 90-206-1326-x.
Gevaar bij de Big Holes; 157 pages; illustrations by Herry Behrens; J1333; ISBN 90-206-1333-2.
De Bandiet met het Zwarte Masker; illustrations by Herry Behrens; J1337; ISBN 90-206-1337-5.
As can be seen elsewhere on the site - very many of the Pocomoto series were published in Dutch editions. If he were to write an alternative series then he might well choose a different pseudonym.
For the books being by R.A.M.:
They are all western books for children.
They are published under a known pseudonym for Reginald Martin.
Against the books being by R.A.M:
No English language equivalents of these titles (?).
Pseudonym only previously used by Reginald Martin for books with African connections.
These editions listed were all published after his death.