Marvel used a tried-and-tested ruse to bolster sales: bagging trading cards (GENE CARDS) with the first issues of each of the GP titles: GUN RUNNER; GENE DOGS; GENETIX and DEATH METAL VERSUS GENETIX. This might have been a relatively new innovation stateside but - of course - cheap paper freebies were an old favourite of British publishers looking for a sales kick.
The thinking was that collectors would buy two copies: one to open and one to keep bagged. Exclusive trading cards would also pull-in card collectors, another hobby area that was booming (thanks to speculators) during this period.
Cynics might also ponder that bagging copies prevented readers from flicking through the contents before buying... and quite likely returning it to the shelf.
Unfortunately, the Marvel UK 'miracle' was pretty much over by this point and the British comics were getting lost in the tide of new launches that were swamping overstretched retailers.
Inevitably, the comics and the new characters they introduced have been all but forgotten today. Which probably means they are due a revival... just to maintain the copyrights.
Cards 1-4 came polybagged with issue one of GUN RUNNER (cover-dated September 1993). Unfortunately, whilst I have that issue I've yet to find a copy with the bag and cards still attached. If I ever do, I'll scan and post them.
The cards below, numbers 5-8 in the Gene Cards set, came free with issue one of GENE DOGS (cover-dated October 1993).
The art is by Kev Hopgood (I think). He's not credited on the cards themselves but he gets an editorial nod in some of the internal publicity for the Gene Pool line. It's an oversight that's fixed on the final cards in the set.
I've posted previous sets of Marvel UK trading cards before, notably the two sets (2D and 3D) that came mounted on the covers of the UK fortnightly OVERKILL. See here and here for more.
The front cover with printed bag intact.
The front cover with bag removed.
The back cover.