Based on the provided information, here’s my analysis of the race:

1. Yaanaas (Total rating: 502.1)
   Yaanaas comes in as the highest-rated horse for this race, with a comprehensive total rating of 502.1. He has an impressive history, having won his two AW novices comfortably and nearly securing a hat-trick on his handicap debut at Ascot, until the winner challenged away from him. He didn’t make his debut until March, and this well-bred 4-year-old could have a lot more ability in him. He will definitely be a horse to watch in this race.
2. Assessment (Total rating: 430.7)
   Assessment is rated second-highest with a total rating of 430.7. He is an unexposed 4-year-old who has won two out of four starts, and showed excellent performance in his handicap debut at Kempton. He was unfortunately withdrawn from a previous race at York after breaking out of the stalls, but still shows significant promise. With an additional 6lb, he certainly has more to offer.
3. Light And Dark (Total rating: 390.8)
   Light And Dark ranks third with a total rating of 390.8. He’s been a useful 7f handicapper in Britain and has the ability to take a hand, however, his tendency to start slowly might be a disadvantage in this strong handicap.
4. Quantico (IRE) (Total rating: 382.8)
   Quantico is rated fourth highest with a total rating of 382.8. All his three runs were in 1m AW novices, in which he conceded 3lb to Yaanaas. Although he was taken down by Yaanaas at Kempton, he is expected to be sharper given this was after a six-month break. He’s considered dangerous to discount on his turf/handicap debut.
5. Helm Rock (Total rating: 377.2)
   Helm Rock, with a total rating of 377.2, takes the fifth spot. He is ideally suited by slow or good ground. His recent performance at Ascot puts him in a good position for this race, although he may lack the scope for improvement that Yaanaas has.

Other potential contenders, based on the positive comments:

Aerion Power (IRE): Despite a lower total rating of 366.7, Aerion Power could be a possible contender. He progressed well as a 3-year-old but has been lightly raced recently. His fourth-place return at Leicester indicates he might just need more time to get back to his top form. The potential drawback is his top weight and the lurking improvers in this race.

Indemnify: Despite a modest total rating of 328.5, Indemnify could be a surprise. He went well last season until a disappointing final appearance, but he’s shown promise, particularly with his maiden success and runner-up finish on his handicap debut at Salisbury.

In conclusion, the race is likely to be competitive, with Yaanaas and Assessment being the top contenders based on their total ratings and performance history. The dark horses could be Aerion Power and Indemnify, who have shown promising performances in their previous races. However, the final outcome will also depend on factors like the condition of the course on race day and the form and fitness of the horses.