Sir Robert was appointed governor of Roxburgh Castle in 1399, in 1408 he was appointed a knight of the order of the Garter, and in 1410 was appointed Vice Admiral of England until his death. This could however be down to later raids in 1410 that he made by sea on the Firth of Forth. The captured booty was said to have reduced the prices being charged at markets in Northumberland.
Georgette Heyer in her novel My Lord John identifies Sir Robert Umfraville as acting as lieutenant for the Admiral of the North "and taking advantage of the expiration of the truce, had put to sea with six vessels, which carried, besides their crews, a small force of men-at-arms and archers, and had sailed boldly up the Forth, doing great scathe.
The Scots were taken unawares, for it was by no means the season for expeditions by sea, and before a sufficient number of ships of war could be sent to engage his tiny fleet, he was away, with thirteen captured vessels crammed with every sort of merchandise, from wheat to wine and spices." (p 427 of 428).