As for the Bobbyjo being a 'trial' for the Aintree Grand National, 64 have gone from the Bobbyjo to following Grand National and 3 have won, 2 of those in the last 2 years. All 3 that won the Grand National had won the Bobbyjo and that was out of 13 winners trying. 15 that have placed in the Bobbyjo have then gone on to the following Grand National and 0 have won.
But I look at the whole trial/pointer/prep race thing a lot and out of the 400+ g1-3,listed,prem hcap jump races I've cross referenced against it none show themselves to be any kind of pathway to the Grand National.