There is absolutely no correlation between the Shoreham accident and a Vulcan being barrel rolled.
In the current environment where every aspect of display flying, aircrew qualification and vintage aircraft airworthiness is under intense scrutiny, not least by the CAA; at best the alleged incident demonstrates a certain lack of awareness of that scrutiny. At worst, it may demonstrate a casual regard for the CAA Permit restrictions under which it flew. Neither example particularly helps the case for convincing the CAA and the public that existing flying regulations are suitably robust.