It would be nice if the stupid barrier vehicle rules were relaxed. Wouldn't be so bad but they serve no purpose whatsoever. In the (highly unlikely) event of a crash, there is as much chance of the barrier coach riding up over the underframe of the adjacent passenger coach as it diving under. Plus the risk is tiny, especially considering the milage Mk1 stock does or would do, and the fact that TPWS and additional safety measures mean that the chances of collisions are far smaller than they were when the safety was brought into question anyway. You are more likely to be killed driving to the station than you are travelling on a Mk1 railtour.
Regardling VEPs or other types with lots of doors, all they would have to do is like FGE did with their 312s and lock most of the doors out, leaving just a few. Would reduce drafts and maintenance costs too.