Found this info from an old book called The Annals of A Border Club (the Jedforest) by George TAncred of Weens, publ. in 1899. pg. 284- In 1517 C. HORSLEY slew John CARRE of Hetton and took shelter in the sactuary of Durham. The old tower of Hetton is still standing and Hetton Pele was held for military service of the castle of Alnwick. Thomas CARRE served as groome of the chamber to Henry VI and George CARRE of the same period was the great merchant of Newcastle whose example in commerce was followed by many branches of the family some settling as merchants at Bristol where they founded the great charity known as Queen Elizabeth's Hospital, others as merchants at Hull, Boston and Sleaford. George CARRE established himself at Sleaford as a merchant for the staple of Calais, trading in the export of wool from Boston to the Continent in which industry he acquired a large fortune. He dwelt in the "CARRE HOUSE" which now forms the site of the Carre Hospital. His son Robert (familiarly known as Old Robert CARRE), became the founder of the great landed wealth of the family.
He purchased among many others, the manor of Old Sleaford, forfeited by the attainder of Lord HUSSEY and also the great barony of Sleaford forfeited by the attainder of the Protector Somerset.George CARRE lived to a great age and left three sons and three daughters. The 3 sons were Robert William and Edward CARRE, succeeding in order to the estates. The latter was created a baronet by James I but died a few years afterwards in 1618. He was succeeded by his eldest son Robert who became second Baronet. Early in his married life when he had daughters only, he made a remarkable settlement of his castle and estates upon the Earl of Ancram, conditional upon either of Lord Ancram's sons Lord Charles or Lord Stanley KERR marrying one of these young ladies.This settlement which was attested by six ministers of state, was afterwards as solemnly revoked on the birth of a son. (it does not mention the name of this son).
Pg. 300 Sir Thomas KER of Cavers had a brother John who acquired the estate of West NISBET. He married Jean daughter of Sir James KER of Crailing, afterwards Lord Jedburgh.Sir Thomas had another brother, Robert KER who acquired the lands of Middlemas Walls (Orkney??) and married Isobel, daughter of Andrew RIDDEL of that ilk. They both had issue. Sir John KER mentioned above who married his cousin Agnes KER had by her three sons...Robert, John and James [Ker] who assumed the name of "CARRE" from their connection with Lord Jedburgh who had adopted that in place of the original family name of KER. After the death of Agnes KER the mother of these sons, her husband John KER of Cavers and NISBET married Miss HOME daughter of Lord Kimmerghame by whom he had several children. The eldest of this marriage was George CARRE advocate afterwards one of the Lords of Session taking the title of Lord NISBET of whom his father settled the esteate of Nisbet. On the death of John KER in 1737 he was succeeded in his estate of Cavers and others by Thomas CARRE his grandson, the only son of his eldest son Robert CARRE by Agnes KER his first wife. Robert was married in 1718 to Miss MILN daughter of Mr. MILN of St. Boswells afterwards of Noranside, who died in 1719 leaving no children and in 1720 he married Helen daughter of Sir Walter RIDDELL of that ilk, Bart. by whom he had three children:Thomas, Agnes and Margaret. This goes one for a ways but then comes to a William Henry KERR, fourth marquess [sic??marquis?] was a distinguished soldier. As Earl of Ancram he was aide-de-camp to the Duke of Cumberland and at the battle of Fontenoy April 30, 1745 where he was wounded. He became Lt. Col of the 11th Dragoons and commanded the cavalry on the left wing at the Battle of Colloden. For this he must have received the gold medal, obverse, the bust of the Duke of Cumberland, which was given to officers who commanded regiments in this battle. He seems to have been an A.D.C to the King. In 1752 he succeeded his grand-Uncle, Lord Mark KERR as Col. of the 11th Dragoons which rank he retained until his death. The Earl of Ancram (William) served as a Lt. Gen. under the Duke of Marlborough in his expedition to the coast of FRANCE in 1758. Succeeding his father in 1767 he was chosen one of the 16 representative peers.
I thought this might be helpful to some researching this surname, but it is probably not new info to this board. It was new to me and since CARRE is the spelling of a name in which I share very close YDNA with even though this is Not my family name (its MOODY/Moodie/Mudie of Nor. Ireland and prob. orig. from Scotland), I thought this might possibly hold a clue as to the link between the family names-Genetically.