Mysteries of the Unexplored - who is JH?

It's Friday so time for some fun - the quiz question is can you identify the artist?

The strip is called 'Intruder on Sestrosian!' and is taken from the 'Mysteries of the unexplored' paperback volume (below). According to the GCD the cover is taken from Steve Ditko's cover from U.S. comic Mysteries of Unexplored Worlds (Charlton, 1956 series) #10 (November 1958) 

Having recently read this book I was interested in one particular story - 'Intruders on Sestrosian'. I've included some images below...I was interested in it because the artists is quite good (no lazy swipes of Dan Dare art here) albeit there are a mix of panels where there is a lot going on and some panels with much less going on.

The final frame also contains the initials of the artist (not many of the strips are signed) and the initials look like 'JH' - but who is JH? Jim Holdaway springs to mind of course but, according to Lambiek, he'd have been drawing Romeo Brown in the Daily Mirror at this point so it can't be him (I'm discounting the idea that the publisher had the artwork stockpiled from years previously).  

EDIT: Steve Holland has now suggested that it IS in fact Jim Holdaway

Anyway, check it our for yourself and see what you think...

Anyway, any help identifying JH much appreciated

Centurions Power Xtreme monthly - issue 8

From issue 8 we again have a diverse selection of artists...
Cover is by Will Simpson (his signature is hiding (again) on an ankle rocket)

'Time Trap' is by Tim Perkins (signature just visible in the bottom of frame one)

Then 'Forecast' is by Steve Ditko. I'll say that again, Steve Ditko. I can't think of any other independent British comic that featured his art. It's only 3 pages, but there you go.

Next up is Michael Slattery's contribution to the issue

Then we have the unattributed 'Arctic attack' - update 01/07/19...Tim Perkins has left a comment saying that this is his work

And all rounded off by 'The Monsters' by Michael Fleisher.