The breeding quirk with the rules (not a full TB) is interesting
From The Daily Racing Form , Apr 4, 2009
The 12-length victory of the 9-year-old, trained by Venetia Williams, was engineered by Liam Treadwell in his first Grand National ride and illustrated the extraordinary dominance that French-bred horses have assumed in British jump racing.
Mon Mome, French for “My Kid,” is a son of Passing Sale, a three-time group race winner on the flat in France and Italy. The winner of the 166th Grand National, he was bred in France by Alexandre Deschere and began his career on May 2, 2004, at Pontivy in Brittany in a 1 5/8-mile flat race for AQPS horses.
AQPS is the French acronym for “other than Thoroughbred,” a stout-hearted, mostly Thoroughbred breed derived from non-Thoroughbred French-bred mares that has helped French-breds, whether AQPS or entirely Thoroughbred, take control of the British jumping world. AQPS horses are allowed to run in jump races in France and England, and the Cheltenham Gold Cup winner The Fellow was among the breed’s most notable runners.