 Gonch and Hollo open a book on Roland s weight loss, offering 100-1 odds for him losing 5 stone. When they find he s doing rather better than would be good for their pockets, they start putting chocolate temptation in his path. Julia s dad blackmails her to infiltrate the next meeting to find out what Freddy Mainwaring is up to. The school handbook instruction "pupils must walk in the corridors at all times" is deliberately misinterpreted at Mr. Scott s registration. In Science, Mr. Scott dissects a heart, which is more than Trevor can bear. For once, the students  attention is completely held by Mr Scott. Banskie offers to take Lucy to the craft fair. Gonch and Robbie dress in white skirts for P.E, because it says so in the school handbook, but find to their horror their wily teacher insists on them following through, and playing outdoors in their outfits. Harriet s increasingly poor condition finally causes Mrs. McClusky to put her foot down - the donkey can t stay at Grange Hill any longer