I can't see it's any different to running preserved locos on the mainline, afterall there were no TOC drivers qualified to drive Deltics, Westerns, 50s, 40s etc when these returned to the mainline. I'm sure the last steam drivers retired years ago, infact the numbers alive must be reducing fast now.
Glad to hear that the need for barrier coaches is being reviewed, totally stupid and pointless rule that is. Might make future unit railtours more likely, as well as preventing the gradual slide to coffin coaches on enbtusiast tours (sort of defeats the point of interesting haulage when you are in an environment where it's impossible to tell what is hauling you anyway).