@Joeblow,
That's interesting, although somewhat misleading. Blenheim Palace was constructed on royal land at the public expense for John Churchill, first Duke of Marlborough, in honor of his contributions to the War of the Spanish Succession. However, the battle of Blenheim was was fought in 1704; Blenheim Palace was still not completed at the time of the Duke's death, but it is certain that it did not exist when Witney was established, it was only started building more than 35 years later.
Winston Churchill was indeed born at Blenheim Palace--the father of John Churchill was Winston Churchill (John Churchill was born in 1650). He died without male heir, so that the title passed to his grandson, the child of his daughter and Lord Spencer. The Churchill with whom we are familiar was Winston Spencer Churchill.
But it is more interesting, because John Churchill, long before he was the Duke of Marlborough, was a close friend of King Charles II (his father had been a royalist and supporter of Charles I in the civil wars, for which he and his children suffered). John Churchill was one of the original "Gentleman Adventurers trading into Hudson's Bay." It helped to make the Churchill family comfortably wealthy.
It is entirely possible that HBC purchased from Witney the blankets they traded, or that they had Witney manufacture them on contract.