i've seen it commented elsewhere that manor books stole a lot of cover art by bruce pennington from covers he'd done for new english library: this may be true, but it is by no means necessarily so.
firstly, manor books re-used cover art from new english library p/bs by artists other than bruce pennington - not least, ray feibush and richard clifton-dey;
and secondly, new english library's owners, times mirror of los angeles, were evidently going through major financial ''changes'', and new english library ltd. were losing increasingly significant amounts of money through the mid-seventies (not least from the combination of a high rate of inflation upon the value of their back catalogue of books' printed uk cover prices, and the glut of p/b titles being published in pretty well all fields as the p/b business moved from boom to bust unnoticed by new english library manglement, who continued to produce their category fiction book titles in print runs of hundreds of thousands, when sales had dropped to tens of thousands - and would drop further for some, to low tens of thousands).
times mirror ended up selling new english library to long-established uk publishers, hodder & stoughton ltd. (and new american library, inc. went to penguin usa, owned by the pearson longman group which included penguin books and its subsidiaries all around the world) - but in the mid-seventies new english library were looking to stay afloat by any means they could - and they'd habitually bought all reproduction rights to the cover art for their books from artists outright, wherever their in-house art department hadn't produced it.
so selling off merkin rights to their books' cover art in one or more bundles where the rights to each cover individually might only fetch £50-£100 (~$125-$250 at the time) - but one bundle might net nel £5,000-£10,000 (~$12,000-$25,000 then) - for almost no additional cost or work - which, at a time when staff below manglement level were being fired or made redundant would have been a significant financial consideration.
- yr hmbl srppnt. does not know for certain, but suspects that manor books, inc.' manglement simply found a cheap source of fair-to-good (and sometimes very good indeed) sf category art to be re-used indefinitely - if not ad nauseam...
cover art by bruce pennington (unsigned, uncredited: front cover art re-used from ''children of tomorrow'' a. e. van vogt (nel 1973 uk & ff.), q.v., back cover vignette re-used central figure & some background from ''whipping star'' frank herbert (nel 1972 uk & ff.), q.v.)
cover price $1.50
224pp? (check) including titles, indica etc, end pp. advertising