There is lend lease and there are loans after the war:
https://en.wikipedia.org/wiki/Anglo-American_loan
Britain needed to retain some of this equipment in the immediate post war period. As a result the Anglo-American loan came about. Lend-lease items retained were sold to Britain at the knockdown price of about 10 cents on the dollar giving an initial value of £1,075 million.[5]
“Under the Agreement, the loans would be repaid in 50 annual instalments commencing in 1950. However the Agreement allowed deferral of annual payments of both principal and interest if necessary because of prevailing international exchange rate conditions and the level of the United Kingdom’s foreign currency and gold reserves. The United Kingdom has deferred payments on six occasions. Repayment of the war loans to the United States Government should therefore be completed on 31 December 2006, subject to the United Kingdom not choosing to exercise its option to defer payment.