OK.. Apologies for delayed response , but have been travelling !
So, this is a more in depth breakdown and what the outcome was !
3 people from one company booked in F some time ago (Lets call them X, Y and Z), a few months later another colleague joined them on a seperate booking but in C, (as prices had leapt!)
Z (the owner of the company) decided to simply book another ticket to allow him to go play golf in Florida or somewhere), and as far as he was concerned "Throw away" his return. That left the 2 guys in F, and once in C.
Meanwhile I was in a separate booking (different company!) in WTP.. The question would have been better phrased as "Can we ask to move the C passenger up to the now spare F seat, and IF SO, move the WTP to the now vacant C?"
I know this was always a leap, but the fact that the owner had already CHECKED IN and had a F Boarding pass (that he had forwarded to his colleague in C) made us wonder how they could reallocate him trtavelliong with Hand luggage only, as he could techincially just turn up at the gate!).
The outcome was exactly as you guys expected. NO op ups, F seat went to someone else !
I DID manage 6 hours sleep on way back though, so there is that !