By Sarah Mills and Marie-Louise Gumuchian LONDON (Reuters) – From diplomatic dressing and priceless jewels, bold block colours and pearls to tweed and a headscarf – Britain’s Queen Elizabeth is known for her unique wardrobe and style. Brightly coloured outfits with matching hats and umbrella trim, black pumps and her omnipresent handbag have become staples for the monarch, 96, who marks her Platinum Jubilee this year. “She has developed her own consistent signature style,” said Elizabeth Holmes, author of “HRH: So Many Thoughts on Royal Style”. “She has the same shape hat, the same silhouette …