Apparently still around, they're on Amazon and elsewhere, but I don't buy mints because the dentist advised me not to! Merged with Bassetts (liquorice allsorts etc.), subsidiary of Cadbury, now ultimately owned by Mondelez. The name probably came from Robert Robertson, one of the founders of the original company in London in 1907.
Next time I'm shopping I'll see if I spot them. From what I remember, they deliver quite a hit of flavour.
