British schoolboy term for a stash of porn found under a hedgerow. It is an ancient custom in Britain that once a jazz mag has come to the end of its life, the owner shall place it under a hedgerow so that it may be adopted by a new one.
Timmy: "Whacko Roger! Hit the blimmin' jackpot last night!"
Roger: "Oh do tell!"
Timmy: "Yes, found some cracking hedgerow grumble down Dale Lane!"
Roger: "Cripes! Better make sure your housekeeper doesn’t find it or there'll be no sherbet fountains for you, ho ho!"