I disagree - we had an excellent demarcation device in the yellow line, which took decades to become embedded in the passengers' psyche, only for it to be washed away in the name of 'innovation' by privatisation - a huge waste of an established regime. In addition, my point about the 165/166s is that they DON'T have any internal labelling post-refurbishment, so we have this situation: newly-refurbished trains that may or may not have a tiny pencil stripe over the windows of first class (or it may be at the wrong end!), while the interior has no labels, no anti-macassars and no other indication of first class. This is based on my experience of the NDL Turbos recently. In BR days I can genuinely not recall a single instance of this ever happening - it was considered (rightly) a fundamental part of turning out stock for service.
Indeed, and there have been/are several units where the '1' on the door is either fogged over/peeling or actually at the wrong end! In any case, it doesn't matter how good the external labelling is, if there is nothing internally it is just as bad, and is unenforceable. It's a shambles like no other I have ever encountered on the railway and FGW/GWR have a long history of it. The privatisation requirements should have included a standard list of labelling requirements, including the long-established cantrail stripes, to be retianed by all TOCs, along the lines of London's privatised buses being required to have a red livery.