Timing is always a consideration, and it does seem notable that this should happen more or less at the same time as England progress to the next stage of the World Cup in, err, ehm, Russia.
Being of a suspicious and cynical disposition, I do wonder whether what comes next is something along the lines of:
Russia: This has nothing to do with us, and proves that others in England have access to this material. Porton Down seem to know a lot about it, and are only a few miles away, Stolen from there. Clearly whoever did this also responsible for previous incident. We demand an apology!
UK; No, no, nothing to do with us. Caused by....... Well, we're not sure at the moment, and are certainly toiling to explain a connection to the Skripals, and know that nobody will believe this stuff survived on its own from the previous incident.
Russia: We demand an apology!
UK: The Police are investigating, premature to comment.
Russia: We demand an apology! Apologise immediately or leave the country........