I suggest that it is the iconisation of the Stubbs portrait of George (later the) IV’s most successful horse, ridden in a distinctive flying gallop by his favourite jockey, Old Sam Chifney; and that the depiction of boots and reins without a rider symbolises George’s disgust at the termination of Chifney’s career by the Jockey Club following a race-rigging scandal.
From the banks of the Rother (almost) via Stroud, Ramsdean, the source of the Meon (just about), Frogmore, East Meon, Old Winchester Hill, Droxford and Upper Swanmore to the source of the Hamble (very nearly). Featuring an erudite parrot, Edward Thomas and John Owen Smith, William Cobbett and Gilbert White, Charles II and Winston Churchill, Eric Ravilious and a 1791 chic doggerel tombstone, and two extinct railways.