Scruggs,
I am sure you are right. I got a bit confused trying to remember what turned around into what, but there were several Concordes at Heathrow at any one time so I cant be sure the 001 went back again as the 004. Certainly the 004 would have overnighted and probably returned as the 002 the following morning from JFK, I think it left about 0900.
Sorry cant be of more help, unsure of the exact details so do not want to confuse the issue.
Lulu