Most of the 71-83 batch are recording anywhere between 595-630k on the clock now, compare this with 45-48 which are 820-840k.  Then compare that to a cobalt b9 of approx 300-400k for the same age.  Also when there’s mid-life refurb it is on the whole concentrated on cosmetic details rather than mechanical.  The TVT are worked hard, and they’re now at the stage of their life where they need major mechical jobs like gearboxes, rear axles, diffs etc.  A harsh winter with lots of salt about also does nothing for brake callipers or electrics, when the rain comes and literally washes stuff away.  There’s no real reliability difference between batches as such (at the moment anyway), but recurrent problems like emojis derates can be hard to track down and fix.