Having managed to access his annual allowance without his trustees' consent, he splashed out on an oil painting by Stubbs, a racehorse, a pair of Holland & Holland shotguns and two Paul Sandby watercolours.
The latter, which depicted local views of Windsor and Eton, appeared at the sale held by Lawrences of Crewkerne on January 18.
Fresh to the market and in excellent condition, they were offered separately and both drew dramatic bidding well beyond their £10,000-15,000 estimates before they were knocked down to the same London dealer.
These high-quality topographical scenes were vintage subjects for Sandby who, along with his brother Thomas, lived on the Royal Windsor estate after 1751 and was given licence to roam and paint throughout the grounds by George III himself. He would often produce numerous pictures of the same viewpoint, as he obsessively recorded the minor details that caught his eye. Many such works are now in the Royal Collection and, while prints of these views appear on the market from time to time, original watercolours such as these are much rarer at auction.
Despite the heavy snow on the day of Lawrences' sale, the auctioneers decided to press ahead with the event - a decision which was duly vindicated as serious levels of interest arrived from a host of buyers.
First up was a view across the Thames from the Eton playing fields with Windsor Castle in the background. The 12 x 19in (30.5 x 48.5cm) pen and ink with watercolour took £74,000.
The second picture, a 10½ x 22in (26.5 x 56cm) work in the same medium, was entitled Eton, View from Crown Corner.
With the college's Henry VI chapel and Lupton's Tower both visible in the background, as well as the exquisite details to the busy figures in the foreground, it appears to have commanded a premium and sold at £120,000.
The buyer's premium was 19.5%