Oof, I actually thought they looked very bright myself but assumed it was just me, reminded me of a particular custom vespa that has been on the scene going back years and years.
I would say too red rather than too yellow, almost a little dayglo looking.
maybe its how they looked new versus a few years in service or maybe its just me remembering them wrong.
the above posted shots did not look as intensely coloured as the samples that were on display yesterday. a definite noticeable difference from other runs of intercity coaches.