The FOs were London based when they bid for LHR years and years ago shortly after they moved from KA to CX, that bid was open to all so was completely fair.
A bit of history here, bidding down to FO from CN was not allowed at the time anymore than it is now. In fact all KA CNs were transferred on a "first officer (rapid command)" deal, they had to wear FO stripes and do a shortened command course as there was no such thing as a DEC. Two guys failed and thus became FOs. One of those two left a few years ago. I don't know if the other one is the one that the OP refers to but would guess that this thread was started as fake news.