Well the supplies were delivered to prevent the English from starving. What difference does it make if it was paid for?<quoted text>
The UK paid for all supplies from the US until Lend Lease, which did not arrive until June 1941 - after the Battle of Britain and Hitler's invasion of Russia.
In the event of a successful German invasion of the British Isles the Royal Navy was to continue the war from Canada, Iceland, Gibraltar, Malta, the Suez Canal and South Africa.
The Royal Navy could not protect the convoys, but they were to continue the war from remote locations. What does that tell you, it certainly does NOT suggest to me that the Brit politicians at the time thought they could hold England if the Germans invaded.