Well as we've noticed, different TOCs clearly operate in different ways, I've physically worked with a DM driving a train as a contingency. He was previously a driver no long before however, so that may muddy the water somewhat
Just this Sunday gone I had a driver manager driving me due to driver shortages. I've also given a train over to a head of function acting as guard due to a guard shortage within the last week. These are hard times and when all efforts are clearly being made to continue recruiting I have no issue with it.
Traditional driver managers who are qualified to undertake assessments, investigations etc. are former drivers who retain full competence, albeit not always over the entirety of the routes and traction all their direct reports sign.
Some TOCs also employ another class of manager, who are really more like administrators, and deal with day to day management responsibilities such as return to work interviews. They don’t tend to be qualified drivers, so this is probably where the distinction lies.
There would be no concern with fully qualified driver managers (and presumably guard managers) undertaking their safety critical roles if necessary, due to strikes or shortages. The worry is where office staff are being trained up as stand in guards who will inevitably lack experience and, as alluded to above, won’t necessarily have been assessed as rigorously.
