This wasn't the only bias. The electorate also favoured British-sounding names over non-British sounding ones. I haven't read the report – it's called Sex, Lies and the Ballot Box – but there's equivalent bias when it comes to horse racing.
Placepots are massively skewed to the horses at the head of each race over those lower down the field. I'm not just talking market order, I'm talking race-card order. This makes sense to me. Most people assess form in race-card order. I'd guess that laziness, boredom, whatever, will lead many to focus on the first horse they know, or a piece of form that looks solid and, having affirmed that horse, either stop there or unconsciously make it harder for any other horse to make their claim. This would be more pronounced in handicaps where old favourites stuck high up in the weights would strike a chord with the casual browser. I think even good form judges are guilty of this. I'd say it's something that gives ratings-based punters an unacknowledged edge.
When it comes to names I'd suggest two other biases. For years Nick Mordin has been supplying stats showing that foreign horses are underbet. Xenophobia, proximity and intimacy, and wanting your home horses/jockeys/trainers to win, combine to leave German, French and, outside of Cheltenham, Irish raiders underbet.
And there's another name bias. All other things being equal, simple, nice or funny names will be overbet. Foreign, complicated, difficult to pronounce and impossible to spell names will be underbet. Want your horse not to be bet heavily by a Saturday crowd of drunken stag and hen parties? Don't call it Posh Bird. Or Nagnagnag. Call it Muhescerharanhsovic...