Sir George Downing

I should be glad to obtain any information respecting Sir George Downing, of East Halley, Cambridgeshire, and Gamlingay Park, or his family. He was ambassador from Cromwell and Charles II. to the States-General of Holland, secretary to the Treasury, and the statesman who caused the "Appropriation Act" to be passed, the 17th of Charles II. The family is of most ancient origin in Devonshire, and I have heard that a portrait of him is possessed by some person in that county.