Fascinating tales, glad I don't have to suffer DV or whatever.
An aspect of the burden of PV that may ring bells is "can't waste a perfectly good PV" when posting/ promotion time calls.
When I reached PSO/ Grade 7 or whatever it is these days, instead of a forecasting post [forecasting was the only thing I was any good at by comparison with my peers] I was offered Leuchars or Bawtry as an admin wallah with 3 years "perfectly good PV" still in hand.
Not that I minded being spared shiftwork or civil aviation or an HQ desk.
PS Defence of the Realm is very hard going I find.
PPS I do love the "rockape in a spelling contest" must tell my son, who was a rock part timer at Scampton.