It won't work. TOC HQs are smaller than they were under BR, and smaller still when you compare the far greater number of passengers they now carry. Take any comparable government or quasi-government body and you will find the backoffice staff are roughly double (in terms of ratio to frontline staff). Hell, in hospitals the backoffice outnumbers the Doctors and Nurses.
Everyone knows this to be true. Why therefore do they keep insisting that a reinstated BR would be more efficient?
Ah yes, because of the glorious free market and because teh state is inherently inefficient?
Have you included the vast numbers of DfT staff and the staff at the Office of Rail Regulation who's only job is to try and stop the TOC's staff from embezzling the taxpayer.
A comparable government owned operation to a TOC exists, it is called DOR, now can you present any actual evidence that more staff per passenger mile would actually be required to have DOR East Coast style business units running every franchise, or are you just claiming it is so?
Before anyone starts going on about the "management pyramid", those staff already exist in the current system, its just that since they are not employed by the Train Operating Companies they don't appear in said statistics.
And define "front line staff", I can make the NHS "manager:front line staff ratio" jump all over the park depending on what definitions I use, most of the people the tabloids decry as pointless middle manager "jobsworths" are simply wearing multiple hats.
"Equality Managers" who only do that as a small part of thier job are then included as managers and not as frontline staff, even though they might be a community midwife who only does something relating to equality for a few hours a week.
But this is just socialist propaganda to distract from the glorious efficiency of the free market.
EDIT:
And before you go on about BR requiring more headquarters staff than TOCs.... TOCs only do a tiny fraction of the work done by BR, you would have to include the total number of staff in the industry per train mile ran. Per passenger mile is a stupid measure since I don't need more staff on a train if it is full compared to if it is empty.
Also I doubt that the numbers of staff at TOC headquarters include the endless lawyers kept on retainer to fight legal battles with everyone else, and the same number of staff maintained at Network Rail's expense to defend against endless claims.
And the huge number of staff required to support the "Delay Attributation Board", all of these are structures that only exist to support your "more efficient" private railway.