Thank you so much layz. ^^

I am indeed a BA AMEX card holder and would therefore book via BA (preferably).

Is my assumption correct that the first leg i.e. ZRH to LCY or LHR would have to be on the same day as the LCY to JFK?

And my question re: luggage: do you know whether experienced TP hunters and gatherers do all this with hand luggage only? If one wanted one checked bag, would this all still work?

Thanks again!