Hi @Phil_Howcroft! I’ve moved this over the Meta, as it seems most appropriate here.
Also, thank you very much for a) sharing! and b) letting me know about the security issue.
In a nutshell, that particular article had some images that were not served securely, so security software may flag it. I’ve gone through and replaced all the non-secure image links with secure ones, and hopefully things should be running fine now! 
(By all means yell at me if this is not the case!)