Ed,
No offence meant, but if you don't know what I'm on about, then you can't be au fait with any form of punting?
You would appear to have gleaned your odds from a betting website as opposed to from, say, bookmakers' ads in The Racing Post? The vast majority of once a year punters will never visit such sites. They're more likely to be watching the Beeb today and listening to what the so called experts are tipping and what the latest odds are for the GN.
For example, on Saturday, the day of the race, most punters will either have a look at either the Racing Post down the bookie's before taking the plunge, or their daily rag before sticking in their optimistic pin.