London CNN  —  A painting by British artist George Stubbs is expected to sell for up to £2 million ($2.5 million) in London next week, as it comes to auction for the first time in more than 50 years. The 18th century artwork of a Spanish pointer dog was last on the market in 1972 when it sold for £30,000 ($37,700), according to Sotheby’s, which is handling the sale. It was first auctioned in 1802, when it sold for just £11 ($14). “The Spanish Pointer” is the artist’s earliest dog painting and