Mushroom publisher Barrington Gray are more widely known for their Gangster titles (see second scan above, great little add for two mouth watering titles) this is the only Sci-Fi/Fantasy title I've ever come across. I imported this near mint copy from the USA for $3, which for how scarce this is was a steal (even with inflated shipping costs)
The cover art is just flat out great, not too overblown with unnecessary blasters and lasers and googly eyes. I can't help been reminded of The Day The Earth Stood Still which was released in the same year. With a lot of pulp artists been under insanely tight deadlines this is a common occurrence with UK titles. it would have set you back 1/6 at your local newsagents.
Wonderful bad ass dame with a gun interior artwork that as nothing to do with te book, but points to the other genres favoured by Barrington Gray.