I've been recycling images that I used on the original version of this blog and that gave me the idea for this particular entry. (In some cases you can click for a larger image).
The cover to Underwater Adventure was reused on the Polish book, Dangerous Marine Animals.
This panel from a Valiant cover feature turned up some years later in a summer special (I'm pretty sure the art is by Geoff Campion).
In the late '60s Valiant ran a Sexton Blake strip based on the TV series starring Laurence Payne. However, instead of commissioning new scripts, they recycled old Maxwell Hawke stories that had appeared in Buster a few years earlier. This meant that Blake's cockney assistant Tinker ended up filling the role originally meant for Hawke's plucky girl companion Jill Adair. Maxwell Hawke artwork by Eric Bradbury, Sexton Blake by Eric Dadswell.
On a slightly different note, I think everyone can see the similarities in these three pieces. The Collier's cover from 1954 is by Bill Baker while the Underwater! film poster, which I think is by Ren Wicks, dates from the following year. Vic Prezio's Eerie cover is from 1969. I'd like to add that I present these comparisons merely out of historical interest. No judgement is given or implied.
As a bonus, here's a look at Prezio's original artwork (sorry it's not a bigger image).
Finally, I see definite similarities between the diver in this Conoco Oil ad from 1949 (Can't make out the artist's signature I'm afraid)...
... and Ley Kenyon's cover to Under the Red Sea that I featured a few weeks ago.